Hadron and Nuclear Physics with Electromagnetic Probes

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nordaH Electromagni

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B . Scho T . rehclaW J. ambchW W. eisW S . Yam d (KE , K. ~ k a z Y

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USA)

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of

Bon,

fo (Universty (Julich,

Germany), Mainz,

Germany)

Germany)

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Germany) Japn) (Universty

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S . Sugimot

Toky,

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Y . ihs akA M. Asakw .I ndoE H. En’yo .0 Hashmot J . Kasgi T . Kishmot K. adeM K. amyurM .T abot M H. Okuno T . amihsO T.-A Y. Sumi K. Tokush

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(KE-Tanshi) (Nagoy

Universty)

(Hiroshma

Universty) (Kyot

Universty) (Tohku

Universty)

(Tohku

Universty) (Osak

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ThisPageIntolyLfBk


1x

CONTES

v

ecaf rP gni epO

.I

INTRODUCTION Hadrons

adres

ot miguS

.S

and

1 IX

- from

T . adustaH

QCD

11.

MESON Vector

op

IN meson

R.

p aR meson

K.

and

J.

.111

production

Fries

,am yuraM Delta The

H.

,ikaz m Y

H.

M.

fo

A

fo

SYMPOSIUM

with

weiv

ME

probes 3

-

MEDIUM dileptons

and

in

heavy-ion

12 colisn

29 fo

q5

H.

spectroy

T . ,imak ruM S.

in

,atiroY

T.

adihsoY hadronic

H.

,ikag maH

Sekimot,

T. ,aduS dna

R.

at

M.

,otuM H.

dna

HADES

IN nuclei

by

exita on

ihc ak oK

M.

with

)noitarob l oC

KE at

meson

,ihsa nuF

,ikas S

0.

,adum Y

excit d

rebuH

THE

nucles

T. J . ,igas K H. Y.

Shimzu,

G.

the

J . ,abihC T . ,atihsapiM Ozaw ,

e (HADES

TO

J . hcabm W

RESONA CES resonac

in nuclei J. abihC physic

mediu

.S

pair

NUCLEON

)53 1( s

NUCLEAR

in in

H . ,oy’nE S. , a r h i M ,ihcam K. H . ,ak n T 523E )noitarobal oC

physic

point

am yuraM

Nuclear

Lepton

nuclear

D. ,otaS Y . arumihsoY

T.

ihsan K

Itoh,

,ikuraN

T . ,urab T

M.

Ishino,

39

No-

(KE -PS

K.

49

AND K.

M.

GSI

NUCLEI Kinoshta,

M.

leir ,

T.

T.

,adukO

,aw k yiM

RELAT D

TOPICS H.

,iustaM

H.

,onukO

16

T.

76 proces 57

X

The

neutral Il-T.

Phot neutron ton

scat ering

Nuclear

IV.

Subthres old

H. M.

dis ntegra io

K.

Retrospect Spin-orb t

section laser

Y.

H.

and

Paryev

S.

polariz t n Yamamura, W. fo

E.

Paul

0.

Hashimo

H. K o h r i , Franz, K . Matsuoka, J . Nak no, Rusek, R . Sut er,

SNOITALER C Suda

Yonezaui ,

Toy kaw

Glock e as oci ted pros ect

split ng

kaon

phot r duc ion

T.

Fuk da,

E.

Saji,

H. T.

M. Tam gaw ,

of

87 Ohta, 93

coliders

L.

Noumi, A . Sak yuchi,

Gun,

on

T.

Mart,

on

H.

and from

C.

Haberz t l

the

701 13

nucleo

the

Ben hold,

nuclei

deut ron

H.

19

Habe rzet l

ELSA

at

hypernucla

l3AC

reactions

heavy-ion

phot r duc ion

producti n

May,

M.

Yam gat , at

Ben hold

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fo

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phot ns

Comp-

f o invers

means

T.

meson

C.

Kaon Miyag wa,

to

S.

yb

Akimune, Ohgaki

H.

K+

strange s and

eB’

81

thres old

10

fo ni

near

ielcun

aspects

K.

prot n

virtual

thres old

Sumowidagdo,

H.

and yb

on

near

the no

induce

Mart,

H. and

on

Jeong measur nt

phot ns

Pshenichnov

Ya.

T.

T.

M.

Maeda

E.

N-

Phot dis ntegration

of

phot production

PHYSIC

phot production

T.

Physic

V.

Utsunomiya, Fujishiro,

STRANGE S

Phenomlgica Hyperon

and cros

I. A . Kaon

pion

Cheon

521

physic

R.

E.

S. M i n a m i , H.

Chrien, Hay kaw ,

H. Outa,

H.

AND

fo

Tamura, 3He

P.

R.

FEW-BODY

731

Saw fta,

and

K.

Y.

Paschke,

*He

K.

M. Miyake, Tanida, at

G.

Eugenio, Khaustov,

P.

Y.

Shim zu,

TAGX

PHYSIC

P.

Mori, Pile,

T. L.

Tang

T.

Kishimoto, Morikubo, B. Q u i n , M . Sumihama, and L.

147

J.

Fkan lin,

K.

A. Yuan 15

xi

nucleo

Phot nuclear

cros forces

G. Quasi-de t ron Two-nucle Quark

VI.

The

NUCLEON

picture

Hirenzaki,

P.

Grabmayr

E.

substructure Lomon

prot n

A.

Spin

structure Y. Sakemi

First Drel-Harn

double

VI .

W.

Experim ntal

W.

Yam guchi

Nuclear

Y.

J . Kas gi Laser

T.

M.

el ctron

Y. Matsuoka, Y. Ohashi, Sak guchi,

isobar

and

of

A phot n

J. K.

Ahn, K . Hicks, T . Kishimoto, T . Mibe, T . Ooba, T , Sas ki,

Tomsiak

form-acts

BY

HIG -EN RGY

391

in

EL CTRONS

el ctrop du i n?

02

HERA

at

K-A

relativ

219

HERMES

yb

29 the

yaw

to

test

the

Gerasimov-

Labor t y

CLAS

beams

at 1.2-GeV

247

Col aboration) parity hig

enrgis

STB

362 -

ring

at

ukoh T-SNL

a t Spring-8 Akimune, Y. Asano, W. C . C h a n g , S. K . Imai, T . Iwat , T . Ishikaw , H. Kawai, N . Kumagai, S . Makino, T. Matsumura, M . Miyabe, Y . Miyachi, T. Nakano, M. N o m a c h i , .H Ookuma, M . Ooshima, .C R a n g a c h a r y u l , D. S e k i , H. S h i m i z u , Y . Sugay , .M S u m i h a m a ,

.H

1

239

and

with facilty

I69

A2-Col aboration)

exp rim nts phot n

deut ron

on

(Hal

the

thre -

183

whom

measur nt

Jefrson

fo

71

reactions

and

L.

role

Mainz on

studie

E.

and

STUDIED is probing

nucleo

at test

K.

charged- u nt

the

the

phot dis n egrat o Kume

efcts

who

rule (GDH-

polarized

4He at

phot n,

Hersman of

physic

polariz t n

physic

Hot a, Fujiwar , Kim,

the

of

FACIL T ES

- esU

Umemoto

and

Meyer

F.

STRUCTURE

neutral-

NEW Few-body

Y.

and

and

D. Efros

V.

for

and

sum

sy tcm

exp rim nts

and

Nag no

thre-nuclo

Leid r mn ,

emison

Levy

K.

of

W.

Orlun,di

S.

High-Q2

section

265 27

Da t e , N.

A.

.2

1

xi

T. ,ar henoY MUSE

T.

yram uS

H.

muisop yS

tsiL

H. T . atiroY

,am yo T

Katym,

tcejorp

ta

the

fo onukO

sympoiu

NEKUF

,aw koy T

K.

dna am yur M

A.

M.

IR

maeb

Yosi dna

Waki, C. yrotcaf

W.

Wang,

.S

C. Wang,

K. 27

M.

Waksugi 285

29

margorp fo

stnapic r

295

1

.

Xlll

Adres

Openi g

Ladies

and

the from

was

On

partic pants

thre

The

physic.

Synchrot n

our operation. wen to topics Probes. through stay

es ntial

steps

toward

in

fo

Toky.

this

the

ew activ es, faciltes sympo iun

Thank

built

role goin resach

pres nt

that and uoy

for

fruit l

of

in

of

4 years

dleif and

wen

your

of

as

thc hig

enrgy

KE -PS to

just fut re

and

and

ew

desolc

has

the

contribute

sympoia

27th

ni

site this

labor t ies. Nuclear

with n t.a

of

country

the dleif

furthe

I hsiw

the

after

SE

eW

at

Physic

al

begin

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sum er

t,his

to

ac el r to

rof previous

opend

inte ds

devlopmnt

think

this

the one.

in

rof

with

first

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ocasin.

i t si

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Japan.

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merg Toky, nuclear

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conlusi,

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campus

particle

Tsuk ba

In

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year

first

evah foreign

in establi h d

Tan shi

the

exprs

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al

SNI evry

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discuon.

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si focused sympo iu

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ThisPageIntolyLfBk


I.

INTRODUCTION

OT

THE

SYMPOSIUM

ThisPageIntolyLfBk

This Page Intentionally Left Blank

Hadron K.

and Maruym

02

Hadrons

Nuclear

Elsevir

ecn i S

and

T.

with Okuno

B.V

(Editors)

Electromagni

lA

sthgir

nuclear

point

Probes .devr s

sci yhp

fo

3

ME

with

view

probes

-

Hatsuda

Phys.

Dept., After

physic

sci yhP H.

QCD

from

-

and

tral dens observal

of

functio s

Kyot

a riefb in-med u

mediu .

Univ., introduction in

in

Special

both

of

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emphasi

theor tical

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Japan cur ent

discue.

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si

and

crit al exp rim ntal

put

They

fluct a ion the on

problems

are

in in-medu

QCD studies.

QCD,

of

selctd

the

spectral

chiral

QCD

orde

functio

topics

sum

par met r

whic

on

rules, si

the spec-

the

in

yek

INTRODUCTION 1.

interaction.

Quantum

Chrom dyna ics The

QCD

action

(QCD)

can

m being the quark mas , D p si t h e covarint derivat . This action has be n wel-stabihd inelast c lepton-hadron scat ering dient her si t h e asympto ic f o the QCD run i g ouplingc scale of a given proces) ncreas:i

scale interaction perturbative car ied (K

wol a orde

inter s g 4.151

-

par met r

(DIS) fredom

(llN,

and

N,

Nf

among

an lyse lso,A p >> AQcD), su t o t r e a t [3]. (Even phenom a

are whic

the quarks

out.

at at

the

very

the extr m ly

takes

and smal

sy tem such

as

f o ev rything

[l]:

in

strength

tensor

y b igh and e+ QCD [2] cr,(~) sa whic

enrgy an ih l t o K

of exp rim nts

leads

(reno maliz t n

to

the

physic

the

into

f o strong

gluon such

hadrons.

the

logarithm c

,:A

dleif as

point

A yek

the decras

the N

and ingre-

dep-

typical

+... number

with

theory

dleif

of

consta

ln(K2/AQcD)

2Nf) -

is t h e

si t h e

r721 =

wher

writ en

,:G

wher

OdK)

be

hig

of

a value gluons

ap ro iate as as

around

run i g

rol c becom

temperature

the

hig

and

spati l

T

20

kaew

factoriz n (K

coupling

no -i terac ng

rovalf

a,nd confiemt

p,

respctivly, MeV.

N

howevr,

consta

of

at

Due

the

T > ), ,A gas

to hig

of [4]

enrgis

hard quarks the

as and

l ew sy tem

the

and

asympto ic and

and and the

as rol c

AQCD

the hig gluons

stil

the

and soft chemial

Deeyb supercond tiv y

may

fredom,

the

si t h e sy tema ic

part in

QCD

wohs

the

screnig

poten ial

can

the be

tsewol

some

4

At gluon

wol

en rgy

self-int rac o s.

scale,

the dynamic l QCD vacu m ap ear from f o meson The cur ent

(1)

QCD This

Any efct

(3)

Interplay part:

Her actions from a uniq e

are

QCD

be

an

from

arbitra y

to

fo

the

theory choies.

q , Q, A

the

must field

predict on:

integra ion

fo physic

fo Howevr,

rew it en to

the

explict namely

ther

si

hadronic

yb

(n, action so

both

A dep n c that dZldA

writ en

at

confiemt

to

hot

chaleng.

ew the

the fields

evig

quark

exampl ,

should

(e.g ,

in =

0.

ni whic parti on

terms

out below. pions

in

hig

colisn

the

and

nucleons),

the

woh rof

the

thes

It

us

on

si

with si

can

a wen also

woh

the

density.

proces.

and

and

into

a chalengi

mat er to dynamics

and

make

obtain

soft

devlop-

ins ght

nuclear

and

the

functio

quarks

then

efcts

CERN

eq.(l) same

obtained

parti on

and

no -triv al exist nc

at

QCD

part no -pertu ba ive

no-liear

categori s: baryon

the

ful

frequ ncy

gluons

[6].

exp rimental

the

One

and

hig

start

rep s nt

hig

at

fo

plasm .

amplitude

to

enrgy

evig

mat er.

to

strong

thre

scat ering

Recnt

alwys

the

quarks

gniwol f

star

consider

eq.(5)

an lytic phenom a

quark

colisn

syaw

quantum

relat d

or

hard

informat

fo

fo

the

f o the informat

dens us gluon

many

. . ;. A ) ]

ful

physic

extract

and/or could

wohs

heavy-ion

mediu .

integra ing

the

to

are

and

hot/dens

writ en

whic

temperature

soft

woh

roF

N,

fo

a result

into

hig

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sevig

as

star

the

becaus

whic

[is;, action

emrg

the

and

nucles-

and to

ev rything,

This

A,

exp

efctiv

QCD

the

and

insde

sa ultra- el tiv s c neutron

fo

a combinat

and

exp rim ntal

in

vari bles.

.I

[d.irdN.

such

in

dleif

cutof

sym etry,

physic

hard si lways them and

transit on

equival nt y

efctiv

physic

hadrons

are

it si stil difcult eq.(l), they are fundame t l lsoa f o the atomic uclei.n in QCD may be lasifedc

hadrons

fo

the

field

is t h e si t h e have

the

the the

hadron- ucle s

si

chiral

Althoug

efcts

exampl s

and

proces factorize

problem a phase problems.

fo

condit s

to

to

with

revo

fZS feS

action isue

theor tical

pro e ti s

-

while

woh

pro e ti s

Since the above in difernt integra ion QCD:

can

QCD

baryons,

betwn

physical

The ments the many-bod undergo s

This above vari bles below.

physic

Typical

breaking

a t extr me si rel vant and lsoa

BNL,

(2)

the

and

structure.

no -pertu ba ive

at ach after

the

gluons

change

fo

eq.(6)

. terms should

fo

fo the functio

the low-enrgy

ygren -wol be

caneld

hadrons. si i n d e p n t

by

quarks the

Both

fo

and

A dep n c A and

efctiv

in

gluons, sevig

5

So

someti

far,

a most

yb one rules

numericaly

enrgy

the gen ral

exp riments.

has whic

Wilson After

and

taking

have

operato

wher

this reviw

par l e

yb

numerical scale

A

The simulat on

great

idea

1985,

In the phenom a universal

a posiblty crit al

ambiguo s

the

point meson

In

of

Among view. Im(

the

in

scaling at

just gos,

QCD fin te

below it

l/a has

in

expansio ;

hadronic

si n o t (the

sym etry one

with

we

at then

car y

si

the proges

hadronic

a yaw

and

l iw

it makes

focus

al.

a typical

out

a being

in

devlopmnts.

sym etry

and

theory

considerabl

rep oducing

rema ks,

practi l chiral

may

descript on

such

quanti es

as

phase

meson-bary

deconfimt

as

theor ical the

a signature recognizd such

both

studie of

has

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det rmin the lat ice

the

quark-gl on

spacing).

in

pro e ti s

esu

actual

recnt

of

the

par met rs of

years

]9[

ap ro iate

in-medu

ap licat on, scale)

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integra o

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l iw various

shift transit on

hadron

evah

el ctro-magne ic

the

as

mas-hift

first

on

of

two

=

the

i Im

to ls evitc f

and

[dqdqdA] This

one

construc

this

in

sort

[7].

in

SZf

fI

eq.(5)

si t h e l a t i c e [8]. QCD sum based on t h e windo of are valid

are

descript on

hadrons

also

transit on

the

that

hadrons

exp rim ntal

imag n ry

J

point

cur ent

d4zeiq

functio s is t h e part (target

formati n

also

lagr n i s a direct

in

are

of

pJTI

the

genralizd

[13],

width-broa eni g

exp rim ntal y, devlop enorm us,

dens

coneti

of

in

in

the

gniwol f

the

Matsui

fo

measur nt

the ideas

not the and

quark-glon

Pisar k models

dilepton

relation

discue functio s

1982,

thes howevr,

in

elihw

In

scalr-io exampl

is, has

observal

EM most

studie al.

spectral and

and

wohs

hci w et

the

pmeson of

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80s.

early phenomlgica

the

as

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er w refncs

in using

of change

mase, ben

Hashimot

the

FOR

various

defin

and

of

theor ical y

started

mas

number meting

we

with

Brown

J/S 1986, In

temperature

the

[ll].

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weN

hadrons finte

I have

chiral

the J/S ylediw

fo

saw

hypot esi

observ

and of

at

FUNCTIONS

eW

TJ )target

hci w

both

in-med u

SPECTRAL 3.

yb

12(

theor ical

t o be s t u d i e i n ref.[1 ] QCD sum rules [15], [17] and so on. Since fo t h e recnt irschegH In t h e next section, the vector chan el implct

product

to

Kunih ro

cq

the quanti y

computer,

recnt

of modifcatns

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transit on and disap e rance

pertu bation

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IN-MEDIUM

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1.2

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argument

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of

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discue

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a meson and

Satz

proved.

plasm

) are

crit al

prosed deconfimt prosed

near

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J/S

shift

of

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[14].

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[lo].

the of

alre dy model in

CUR ENT ni

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this (z)

QCD,

Jv(

the

0)

I target),

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time-ord (the

from

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cor elati n functio )

functio as

point

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(7)

6

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/target)

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,J

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el ctromagnetic

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physical

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matrix

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into

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Im(TJ ),QcD is dep nd on t h e mediu by t h e the direct lat ice exact spectral functio This QCD sum spectral shift as ~91.

Lat ice

lat ice

t h e properties the quench d % with 5-10 in ac es ing the lat ice conti ua on no -triv al Rec ntly QCD data

can

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hadrons

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time.

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does

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constraints rules predict ons

in

pos ibly

on

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measur ments

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cal u ting particular,

agre

is higly [21].

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on

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rules

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rules

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8

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posit n

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Basic

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s

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at

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ME

K(T, Monte

N,.

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fo makes

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with

data

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as umptions

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MEM

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lat ice sum arize can theor m,

condit al be

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si

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L

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on

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al

the yb

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si S P F K(T, w ) si pro ti nal tA eroz temp ratu e

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nevig

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to

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number

on

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than

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ni

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an

problems

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=

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rof

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w)

mat er

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likehod standard

x2 -

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functio

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proba il ty).

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;2 =

exp(-L)

DA ( . j ) .

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si a normaliz t n D A ( ~ z ) si x N covarine used in t h e

,2

difernt

and N be

o

T S,

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m

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as

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=

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A(w)

gol

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-

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data being

avergd

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genraly

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the

number of-diagnl

informat

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argument

revo

hand

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strong be

side

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entropy,

temporal cor elati ns [24]

configurats of

with

wohs

(17).

C

points

par met rs

that,

fo

si among

an

C.

for

to

9

si a normaliz t n

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the

and

functio

a:

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sta e-of art

the

ME

[2 ],

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default

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a real model. output

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/AY(w) =

wher

factor. caled

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positve

par met r

Aout image

and

is nevig

yb

m(w)

is

a weightd

a real

and

averg

revo (20)

d ~ ,

si o b t a i n e d

yb

maxizng

the

fre-ngy"

"-

Q~QS-L, rof

a given

dicta es and that degrs

(21)

the

a ap ears

Find g

(SVD) 4.2 .

with minor

modif cat ns

a =

L,a

1.69

=

f,ocN

direct on.

eW

that

os eW

integration)

wmas

eW

pPs,"(w

T

In

The and

data

for

rof

and

in in

the

lat ice actual [26].

par met rs

for

VeM

GeV.

(V)

K

the result yb of o m images the broad

be

roF adopt

(b), =

ew exp(-rw).

chan el factor

s i not have

structure

data,

and lat ice

PS

0.157

nesohc (spati l)

and

at V

Dirichlet

to reconst u d

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unit

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Figure in-med u

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n-+7r

the

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line)

el ctromagne ic

emison

rather to the the hadronic Quark-Gluon 0.5 mas e ). hadron The of e q . with n 02 AGeV) state ( a t hig measur d .fc Figs.5 with Optim s cal y QGP hadro-c emist y further

[20]

cur ent

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-

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l ew

(as

GeV to al

)1 (

this

hadron

in

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data

’thermal’ decays 6.

172-42[

the

invar t ,rev woH

[30]

are

(cf. one

boundary data

[2 ]

density- emp ratu e

esntial

]13[

rates

in

and

hot

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O(&)

thermal

as

compared

as

yield or

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at

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has

the

conlude

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reminsct

panel).

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a sub tan i l

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at

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descript on include

stil

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0).

with esolc

at

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+

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M alre dy

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scenario.

line),

sta es

phot ns

as a gnirewol ap ro ch towards reaction si obtained yb eliforp rof a nevig colisn tA CERN-Sp [23] simulat on . si domina t revo (or a t least M ) a n d hard in t al rocesp such as mas range M N 0.2GeV. A consi te ecno hadronic many-bod ef cts this point lsoa t h e drop ing mas scenario urvec in Fig. 5). that strongly interac g mat er ben bservdo a t the CERN-Sp. Other upresion ]23[ also sup ort this substantiate t h e presnt sta us and resolv

a onsequc in a heavy-ion comp ne t

a simlar efcts

boundary production to

q

mat er

functio

functio ; mediu

sug e t d

the

i

n

cor elati n

(dashed- ot ed

cor e ti ns ben thres old

thermal

revo

transport

phase

Plasm

lines)

temp ratu es

phase

I t has

duality

the

as

(ful dilepton

the

m

fre in-medu

-

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with) of [20,89]

Nonethls,

the

hadronquestion .

such

e.g.,

final the

as

21

[

CER SINA45

/

Pb(l58AGeV)tAu

-

10-

1

2.0

5.

Figure CERN-Sp elc tail’), tion decays

4.

CONCLUSIONS

chiral informat excita ons the chiral when

This

resto a i n

Low-mas

[25]

talk

meson

frezout

lines:

has as

Acknowledgmts

It many

si

a pleasur fruit l

(hadronic

co ktail

l ew on

discuon.

on

in

the

nuclear of

GeV ind cat g

spectral a broadeni g

as simlar

evalu ting The ap licat on ni recnt heavy-ion 0 to 2 data romf production rates phase boundary of t h e quark-h dron would lsoa cor b ate transfe in t h e transit on In t h e near fut re RHIC (adv nci g a t GSI. Thus el ctromagne ic understandi g of

8.0

exp rim nts

first

fotings

in duality

strong

to

enrgy

G.E

cal u tions

at

inter la on

interac o

thank

swoh

pertu bative that

from

furthe t o a wen

of

the

sum

restora ion

hadronic

dilepton observal

The

whic betwn l iw

E.V

in

as l e w

Shuryak

be

vacum taken

be

of acordne

yb

exp ct d

as

the encod

decras to

might degrs

yb

the

and

precison

of

H.

schemati

an

hadronic vicnty

PHENIX contiue

Sorge

throug

around

as of

the

exp rim nt

exp rim nt

the

rof

proges

col ab r ti n

3.0

the from

to

with

consta

descript on

’

’

empir cal low-ying of

of

decay

and

fredom.

"

compared contribu ons

treatment

ap ro ch pion

I

at

con e ti

observal

of to

spectra extrac ed

in a variety

the

a easonblr in-med u ni t h e b e realizd s i located the

ap e rance A

!

5.2

as

[24]

radi t on

with

T "

2.0

1.5

phot n

lim ts

meson

struc es.

temp ratu e/d nsity

Ic/VeG[

,q

Direct up er exp rim nt

vector

leads

struc el s

partonic

featur s

the el ctromagne ic

an ih l t o

can physic.

Brown,

yb to

q

to

data

frontie )

In thes

thermal

[ 11.

line)

rule. CERN-Sp

mas .

08AW

char te iz d resonac

that signaled

chiral

thres old

are

the as

mat er.

0.1

\

" " " " ’ ’

’

0.5

6.

Figure CERN-Sp: the in-medu (ful

the

parti-

modifcatns

hot/dens functio s

model

invar t

the

mediu

’cok-

an ih l -

m

mat er Weinbrg

thes

resmbl

+r

in

at line:

’

" "

0.

1.2

0.1

spectra

focused resto a i n

hadronic

IGevl

0.6

dilepton

; Dashed- ot ed

ind cated.

sym etry

a1

, M

after

other

as

0.4

1 20AGeV

m in-med

’ 0.

centralS+Au

I’

of

towards

measur d of

the

dilepton

exp ct d a reduction 1 . 5 eV.G mo entum HADES

It 143I

[3 ] our

in

and

at

28

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and

Universty

e t a l . (HELIOS-3 e t a l . (NA50

and

Phys.

(190)

Phys.

507.

(20 ),

B25

Rosa-Cl t,

Phys.

Rev.

Phys.

.M

Phys.

Let .

and Workshp

Brown

Bratkovs y ,

Phys.

Bubal

ACTP

and

Let .

Nucl.

(1967) Norenb g,

J . Wamb ch, A632

e t a l . , 08AW e t a l . , CER S

C.M Nucl.

453.

Phys.

Nucl. Rap

Rev.

W.

Nucl.

Phys.

Nucl.

and

I . Zahed, 81

Adv.

13.

Phys.

Mosel,

Phys.

. P iavkL

G.E

E.L

e t al.,

and

Gale,

and

in (198)

Weis,

U.

Let .

Schuk,

KO,

,ef oI Ericson

and

W.

Shuryak,

Rho,

ap ear

B.

.M and

Rev.

J . Wamb ch,

and

Angelis

and and

to

B427

405; P.

(20)

Phys. B.

Lenk it,

63.

Bordal

539;

e t al. .02

G.Q

iL

Hadron

K.

’

and

02

Maruym

Nuclear

Elsevir

po

meson K.

Maruyam

the

Electromagni

Probes

sthgir

lA

92

resvd.

nucle s

Nuclear

of

vacu m

det rmined values.

op

requi s

Study,

Tan shi,

(3He)

ident f

For

a variety

Althoug . mas decays fo modif cat n.

exclnt

B.V

(Editors)

predict

has

in

Toky ,

be n

the a modif e - as

tested

coher nt

of

Japan,

modif cat n by

by

While.

Univers ty

18-02

in

a tag ed-phot n

phot r duction

using the

Toky

the

the

mas

Soding invar t

T+T-

contribu on

exp rim nt

proces

model

mas

in

spectrum

fo on

par met rizat on spectrum

ad it on

the to

the

at

nucle s.

are

observ d

the

meson

op

Toky.

consi te

in

vacu m- s

The The

op

the

incoher t

in

nuclear meson

mas

with

and

po.

INTRODUCTION

such mas e one

brief

3-21,

Theor tical y

.1

easi t

Scien

with

Ohno

a

for

mediu are width the proces

sci yhP

H.

in

aCent r Midor -ch

in

and

(3He).

as

the and

belivs

mas

the fo

nuclear measur ment the

decay

This

in

The candi ate

the mas f o r Nuclear GeV Electron of 52 me b rs

widths that theori s

mediu . many

predict Thes

theor tical mediu

particle

a direct

Study.

fo

fo

Synchrotron from

predict

to the the

the

predict ons

is in

by

(the theor tical

lightes

and

op

9 insti utions

theor tical meson

(ES)

fo

A direct construc ing

thes

of

the

Toky

yb

are yaw

topics

mas - hifted

3He. fo

to

the be

is t o the

det rmine invar t of

meson)

The (INS), four

Then, TAGX

measur nt countries:

in

Two

using

sev ral

models.

have

the due

reviws

the

are

bag

vector

predict on. in

ther are

A

det rmination

status.

the

theori s values

modif cat n

pa ers

hand. mo enta.

examine

Univers ty

in v a c u m , models. yb t h e

exp rimental

exp rimental

meson po

exp rimental shift

hadrons

the

nuclear is

sum ary

f o the

consti uent-quark

types be n

true

tested

are

(ES134)

hadron

mas avilbe

the

talks

meson in

physic

con e tra e the

1-GeV Can da,

exp rimental

mas structure sel ct d

col ab r tion,

topics. car ied Italy,

phot n

Lat ice

yb

at

pres nt

mas from

the

Proce dings on

a exp rimental out

Korea,

measur ments

the

in

vector

[1, 3]

the

the

si

mas

widths.

the

of

cal u tions

models.

observations,

and of

from

thes was

f o theor tical

mase

the

po

is

the spectrum by

peak the

to I ilw

examined

and

nuclear

While, observations.

beam whic

direct whic

signal mediu

hadrons make

at

from

meson

no

hadron

I wil

The and

the

[14, 5] Insti ute

is consi ted and Japan.

fo

the

as

the are

a very test fo

the

1.3-

03

PHYSICS

2. 2.1.

The

in Q u a n t u m is resto d decr as exp rimental y sym etry Chiral in t h e the enviro mental sym etry f o the the values Mas - hift cal u tions QCD hadron rescat ering dep n ce Al

density describ be normal 2.2.

ekil

shown

such

rules

mv*

time-l k as

proba il ty

etc.).

yb

are

find g

this

that a hadronic

in

it w i t h Table 1 list get a hig decay is t h e best soluti n.

the

the proba il ty

pro e ti s

Hatsud -Le

The

on

observ to

in phot n

observing

change

Rap

place vector-m s n vacu m. insde

to

the

shift.

The the

nuclear the

det rmine

fo

the

the is superio

thre

po det rmine

mas

restoration

enviro ments

given

one

by

that

includes

Asakw

the width

density by

yb

sym etry

QCD,

) dep n i g fo

and/or

are

constant

yb

predict

(9s

restoration shift

interac ions

The

coupling

partial

nuclear-m t er

the

decay

of

the

meson

type,

of

change

the

(a,)

and of .]31, [

on shift from

model et

mo entum

is

the

Chiral

some

Brown-Rh

al.

[3], [16],

particles,

lightes to

the

the

spher

the vector hadron

enrgy,

po

at

parent one

can meson

is t o

particle

mas

and

the

with

the p, w, the method

as other,

in

mas

a certain

det rmine

meson as

the

efcts nuclear

nuclear size and

shortest

in whic

space-

mediu . losing

(e+ -,

proba il ty,

takes

One

the

mediu .

has

4. In orde produce

efil

its

and

nucle s

mas ,

to

the

T’T-,

fo the

to

whic

it a t

shift.

withou

pairs in

mat er

i t is predict

det rmine

The nucle s

the ,o*

rc a par met r

wher

meson

fo

the

into

vacu m,

and

observ d

vector in

the

a,

be

decays

nuclear

in

pres nt

pro ag tor.

the

magnitude

meson

mas

density,

at

might meson

the

nucle s,

is predict

Lagr n ia

cal u tion

and

to

mediu

the

information

to

vacu m.

gluons

cal u tions

mediu

the

orde

thes fo

[17].

conde sat partial

and

expr s ion,

In

a vector

ins de

[12],

al.

to

ef ctiv D V M

in

strong

normal

vm nuclear-m t er

exp rimentalis

vector

nuclear

Chiral

the

the

the

at

of m a t e r ,

predict

si due

gniwol f

nucle s,

place

in

decr as

hig -mat er-d nsity

This dicta es

et

the for

si t o yaw

antiquark-quark

a s in QCD-Sum R le

4 nev

in

out

l ew

broken

wher

This

theori s

in

yb

normal

blocks

value.

and

task

takes

build ng si sponta eously

meson

meson modif cat n

By

.1 mas

The

p, w,

in

p the f o mas

and

the

in

car y

dep nds

fo

hypot esi by

pos ible particle.

decay

Figure

enviro ment. vector

the direct

is

values

Many

as

theori s

as

mas

vector

it

cor e t.

density.

a feasibl

region,

The particles

be

for

po

observ the

more

to

colisn,

smal

sum arized

the

magnitude

fo

cal u tion [la].

quarks, (QCD)

hadron

such

such scaling

density.

shift

in

as:

is

to

asympto ic

baryon

Le

mat er

an

betw n

high-temperature Lagr n ia

cal u tion

enviro ment.

the

0.-25,

in

proved

vacu m. formulae

by

predict ons

take

decay

meson

in

sum

region as ume

in

breaking

How

Mas

reach

hig -en r y

expecta ion

vector

= CY

the

also efctiv

vacu m

predictions

sym etry

Chrom dynamics

in

to

fo

K+-

the The as compare

Theoretical Chiral

wher

place

eW to enti y

MOTIVATION

and time

to the

13

Table The

1

lightes

vector

( MeV/c2)

Mas

Width cr

(fm)

rle r

meson .

(MeV/c2)

15 . 4.5~

meson

fo

becaus

the

of

nucle s.

w

287

3.1

i t weakr

interac ion

3 x

loe5

0.9

to

4

910

8.4

23.4

7x

1.0

rhadrons/r

vector inter o

P

867

produce

the

vector

4.

4. 0.84

meson

ev n

in

the

DO

M,,

son fo

Figure

wher smal er

1 GeV,

2.3.

mas gets. (1) (2) (3) (4) No

the

.1

ins de

nuclei

en rgy.

the

the

ins de

produce the the det ct exp riment

numbers

than

Experimental

Bertin

The

Decay

and

VM

procedur VM

are

p is t h e difernc those

nuclear

proba il t es

cal u ted

mediu

using

pro sed ins de

with this

of

[19]

is:

MV ins de

radi

hig er

design

Guichon

velocity.

betw n

are

at

a stable interacts decays the particles

of

to

the

nuclear

reconstruc method

the

as 3He

en rgi s.

At

a functio

the

nuclei;

and

(TAGX yb

around

the

mediu ,

nucles has

of

Pb,

a method the

using

Figure mas

-em

op

si

"p

options)

nucles

by into

the be n

with

efctiv

two

mas

"p

shape AM

measur ment meson the particles,

car ied

mas

mas

pendi g if cat on.

fo vector

spectrum,

the

A

2.

(MeV/c2)

schematic l shape

shift

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fo

phot n,

out

up

mas .

AM.

is

in

Broadeni g

a two-peak is t h e signal

phot r duction

MV

of

whic

to

now.

the

vac um

a super osit n

fo the

vector-m s n

invar nt

T+T-

on

and structure

that

fo

mod-

mas

nuclear

(VM)

tar-

the de-

32

(1) interval (2) pairs. fractions phot production producing el ctron

eW

have

to to

examined

reduc

and

escaping

interacting

reduc

(3)

fo

the to

the

the

ac el rator.

What

The

mas spectrum

shift

mat er

al. than region MA I- 1 3.2.

this, proba il ty

takes

decays

to This

to

escaping

density,

change

the

nuclear due

the

lepton whic whic

is t h e light

from in

signal place

decay

spectrum.

final

pairs

the medium,

condit ons

the

nucle s. are

the

1 show

to

and

reality.

two

mas

the

has

min um

fraction

heavy

that

measur

nuclear

test

use

the

decays

spectra.

the

production

points.

fo

reduc

light

be

ad it on factor (TAGX

e+ -

large.

is

reaction

and

outside.

2 show is i n t e g r a t i o n

the

to

lepton Decay smal beam

the

options): fo

the

low,

(1)

and

pions

bad just

option at

over

(2)

the

When

resulting

are:

JLAB

the

not

a schematic

time

be

fo

pairs,

FSI

nuclei

ins de magnitude,

decay

They

enough

should

el ctron

)-ri.+n

Figure

spectrum

should

test. give

MV

det ct

operation

delay d.

to

fo

both

mas

lev

instead

3He(y,

in the

be n

to

the

fact

hig -duty

befor

and

fo

(FSI),

radius

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nuclei

a sign f ca t

with

experimental

nucle s,

and

the fo

a prompt the mo entum

interac ion

av il b e

the at

decay

nucle s

In

space,

a hig instead

the

the (-lop5).

smal

a hig -cur ent, be n why

the

nucle s

from state

signals,

not

reason

has

the fo

interf MV

are

had

the

Figure

? ins de

ins de

mas mo entum

to

nuclei options

that

fo

requi s

threshold.

the

a superposit on

section

use TAGX

si

proba il ty

with

cros is

phot produced

distortion

condit ons

mas nuclear

the such

EXPERIMENT

3.

than such

is

invar nt

7rf -

3.1.

VM

enha ce

VMs phot ns,

Our strategy use VM-m+.lrt o compensate suf ering befor The decay a t lower en rgies. po meson production 2.4.

the

SE as

An

A

[20],

Photon sup lied 1 .% idea lO%-duty

TAGX magnetic

This

the

was

and above

and

beam a tag ed-phot n smal

pres nt it

pro sed

1 GeV. CEBAF.

factor

spectromet r spectromet r

was

number

pO-meson

to sucefly Figure

had

extend be n

has production.

3 show

beam

fo

not

av il b e,

realiz d

the

en rgi s

be n duty

the

up

ap ropriate in ac el rato s

whic

factor 1987.

with was

1.2

to

The in

the

GeV

rof minor tag ed-phot n the

the

coin de

with

a duty

investm n best world

in

the

befor

world

measur ment

factor

fo

by

beam the

in

operation

Yoshida with the

with a large solid angle f o r 7 sr h a s be n constructed gen ral-pur ose det ctor f o phot reaction measur ments y b using the hig er-duty beam in 1987. This TAGX spectromet r was used orf a n exp riment that realiz d design in t h e prec ding section. I t asw for t h e measur ments f o t h e 7r+7rT phot production o n t h e 3He nucle s in t h e -/E region losec t o t h e op production threshold. No measur ment of op p h o t p r o d u c t i o n on any nuclei has be n car ied out so far in t h e 7 E region. The experiment used the tag ed-phot n beam and the large- c ptance TAGX tromet r [al a t the 1.3-GeV ES. The phot ns (5x105 s’,1 in i n t e n s i t y ) with en rgi s 0.8 -1 2 GeV ( 5 MeV in t h e en rgy resoluti n) erw inc de t o n a cryogeni 3He

les et

more

en rgy

fo

as

factor

a

the

spectar-

fo

3

z .c

CEBAFJ

4 -

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w

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g ;

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~. ~

1

’07

A

1

MIT-Bates

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0

get measur d velocity vector pion ev nts used for wer mas 3.3.

fo

ined mas

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3.4.

col aboration. Regina, this

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ev nts

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TAGX contribution.

les

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in

g/cm2 simultaneously

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-

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0

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experiments, meson ac ount distance gives

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4 MeV/c2,

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MA l ~-

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ai

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TAGX

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(~,x+T-)

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measur ments

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phot produced wer an lysi

particles

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data

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Toky ,

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decays

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absolute

smal er

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et

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fo

[2]

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et

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po,

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for

tif

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op

al.

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they

exam[21].

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mas

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wer

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and invar nt

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width

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pions. into

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particles

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(23cm)

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reco d

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particle

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charged

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SE

to

is r e c o n s t r u c t e d t o be t h e invar nt mas yb loking for t h e nar ow- idth , K whic the ongerl efil f o ,K f o c ~ = 2 . 5 4 cm betw n the T+Tvert x from the beam TM distribution (Fig.5) hows a clear peak. the peak posit n t o b e 0.6145 MeV/c2 consi ten with t h e ,K a s u m p t i o n . eW obtain and AibfT,=20MeV/c whic a r e much

an lysi

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Figure from other Those with

Tokyo

thicknes ).

mas cor e ting

~,

0

a cut 19.9f5.4 ac ur y

[23].

to

The si

the the

width.

In

in

34

Figure

A

4.

schematic l

layout

RESULTS 4.

4.1.

is

sit on

Production

Ther

production that that nucle s coher ntly quasi-fre

867 obtained threshold

AND

po

breaks the

mechanism

phot n production

av il b e MeV/c2), The

make

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mechanis

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the

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incoher tly. 108

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the

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nucle s

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40r

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50

400

600

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Table Mas the Mas 747517

Soding

(2) to the mas ac ording the 4.2.

matical

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2

width

(MeV/c2)

incoher nt (4) 7 5 3 ev nts and

production

M

wher and o M 151 21 is signfcatly the shift outside Pos ible skewing and the

the

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region.

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data

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table

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r

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whic

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7

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600

800

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Figure

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neither phase

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8 show region. filed

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are

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[24].

T+T-

dif er nt

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model. mechanism

det rmined

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the

.0-a cros

other

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threshold the as ume

mea-

section as

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a

se n

in distr The

The

with

difernc do

the l ew not

or

31

improve region. Yam z ki-A a shi target region density, the 0

large fre are the er o also modif cation

the

rep oducib l ty.

Another

This

mechanism nucleo

Saito-Tsu hima-Thomas quark-meson meson

A tif

50-6

modif e ,

MeV/c2 is n o t

that mas

enough

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are

to

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cor elation the

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model

they

estimate

in

[27]

no deform

with

when

this

experiment.

predicts

under

get

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the sur ounding

the

237-5

the pres nt fo the fre po t o be det rmined by 9 and listed in in Fig. X2/dof from 8.9 t o 2.0 subject t o change when ( 2 ) the col is na broadeni g si t a k e n into ac ount.

with

par met r

shown fit ing

[26].

and

whic

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sum

wol

mas

mas

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Table

fit ing,

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fo

mat er mas po

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sati f ed.

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formula

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)1(

does

to

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op

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mas - hifted

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30

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width fo

work.

using

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results and

its mas

1

E K

10

0

60

400

80

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the fit ing

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with

400

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500

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Figure with shifted space ducing

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shape the

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800

900

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po

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proces .

mas

A

shape, and

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in

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CONCLUSIONS

5.

tested serv d

in

10

Theor tical y

by

have

a tag ed-phot n the

predict

mas vac um

mas

exp riment

modif cat n and

the

vacu m

at

Toky .

fo

the po

width.

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meson

in and

thes

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nucle s confirm

po

meson

has

be n no

by

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0

5

FP

20

mo entum

3He

meson formula

in

than

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po

=

10

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potential A substructure hig er in

fo is

MeV/c2

spectrum

ap roximation. the

as

inclus o

.

-Seding

mas

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field

40 o

aver g

60-7

the

a mas - hifted.

value is large,

the

nucleo s.

density

condit ons

and

the

ef cts

Obtained

as umed

mechanis

mas

ob-

is

83

Table The thre are

3 7r+ iT-

fixed

invar nt

contributions:

in

the

Mas

(1)

modif cation have reduction

the

in

mas

fit ing. (Mef/c2)

65 k8

(2)

by

mas

spectrum

po,

in

mas - hifted

(2)

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incoher t

Width

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production

that

%.

proces

phase

is r e p r o d u c e d Numbers

space.

with

82&14

Incoher ntly as umption

an

that

by

without

Relative

mechanism.

s i consi ten

and

po,

(MeV/c2)

15 15

768 the spectrum

15

(1)

a sum

fo

er o s

fraction po

18& 4

produced

meson

7riTf-

the

meson

op

mas

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35.

and

nordaH K. am yuraM 20

dna

’

raelcuN

dna

reiv slE

Nuclear

sci yhP H.

ecn icS

onukO

.V B

H.

Mihar "

K.

.S

En’yo

*

Ozaw , Yam da ,

(KE -PS E325

J.

a,

0.

Chiba

, T. .S

sthgir

1-

"CNS,

targets, prima y run ni in / 3 7 1 a b shape observd mas -nu ber signfcat

should subject difernt observati n nature *Pres nt ’Pres nt

the in

carbon

EPlB

repo t d. space

dep n c dep n c

p~

Kyot

at the The with n

mas of

T.

and of

spectra the

has

lead.

production

ben

in

of

sta ist c

in

The

Prot n

kinemat c l 5 q meson the

Ishino", M.

K.

Nomachi

H.

dl

Tan k b,

Japan Toky,

Ibar ki,

KE

.M

Jap n

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decays

Ieir b,

Naruki ,

Tab ru",

60-852,

108 -5 3

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t

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3-21,Midorch

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VeG-21

nuclear

the

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observd cros

observd

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on

section

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observd

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to

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physic

visble.

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at

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observd

1 to The that

3

oN

INTRODUCTION

1.

obtained

Y.

Ham g ki,

H.

Universty,

Toky,

observd

wher

of

and

Universty,lO-1

polyeth n , beam-lin 197

Sekimot b,

H. Murakmi"

Ibar ki of

have

T.

Kyot

Universty

eW

Funah s i",

.M

KE

at

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Tsuk ba,

Osak

93

4 meson

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dRCNP,

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pro e ti s

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Univers ty

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of

si improved

hadrons.

li

The

With lepton out rate onlie data crates sta ion are to the

from two

in

yb

ycnei f

particles of

scint l a ors

det c ed

(TOF)

prot ns

a scint l a g

has

be

Flight

sc.)

target or

from

trig e

841

prot ype

showering to < det c ion el ctron of inters Only reachs

3.4.

of

and

scint l a ors

to 50ps)

l iw

108.

=

Time

GeV/c altoge h r

(0 to

phot ns

No

the det c or

work-

VME

The

yb

54

field

3.5. already conducting

Status

Although

instal ed map ing

cave, while sy tem, det ctors physic

Figure AGeV. conversi chamber. one The heavy showed o r ev n acquis t on (8 s t r i p s ) intensit es typical routinely particles suc e f l y

beamline, equip ed

and runs

2.

fo

ion

magnet

and

Note

stable beyond

time

panel:

in

has

ATM

target

operation

util z ng

reach d

det ctors

to

the

fo

has

C+ design worked

diamond lev

los

the

the

E

amplif ers

fo

fo

reliab y with o

go d

image

operated

1.2 =

=

under

10

a time

The

and

used

(peak-to-peak) I

I

proces ing

panel:

about

and

-

at

coin de

AGeV

inte si e

new

sa resoluti n

150 04

alowed

heavy

up

av il b e

for

in-beam

o

wer mV.

unit.

The

lo7

trig e TOF obtained. while The

compone ts

at

a cur ent with fo the

el ctronics,

integration

after

colisn

+

to

1%) two

or

track

Di s t r i b u t i o n central

2 . lo5

Ar

T)

ion

el ctron

many

com is n g

The

and,

sucefly

ps

(
n->p

-

---

(fig

(fig

la)

Ib

n)

w/of shel

03

.5 v

0

E 20

10

0

Figure pion,

cal u ted

2.

Total

cros by

section Schwesingr,

40 20

fo

the

60

4N) and 4He(7r,

Wirzba,

10

08

(MeV)

,E

proces Brown

120

versu

[2].

to al

en rgy

fo

the

incom g

fo

r n

r-A+

+-

while

)-r72

Clebsch-Gordan fo con lude

TAGX

are

twice

0.59 that

only

clear st

evid nc

that

at

body

mo entum

yield

-r72

of

INS

(0.3

A

ypn

+-

ac eptable

< 052

ev nts

cal u tion,

A

as

en rgy of

has

Asai

betw n

competing

MeV/c

]7[

from 570

the

whic 7r+-pnl

-+

ind v ual y wer

A

measur d production

Howevr,

mechanis betw n

to

phot absorpti n and

850

MeV,

neutron

as

the

is

the

observ d

d(y,

the mechanis :

ac ording

to

two

exp cted

charge yield

studies and

7r+-p)n

to

using

employd

reaction

a spinyield sta es. ratio, the Monte

a specta or

np-r+ 7 --f

fits

al.

with

A+ Anot

come

ratio contribute

r+7r-

+ 1p-r7+r7

npy

et

exp cted.

the

bal nced

mechanis

f 0.14)a~~.

excita on

(Toky ). with

space

resona c

a more

and

A++r

+-

phase

mas

many

=

beam a number

fo

as

provide

~ A A

delta

Four hig er

coefint

so

quasifre

yp

Double

an lysi

and

phot n

Quasifre

This mis ng

f 0. 14,

nearly

spectromet r a tag ed simulations

using Carlo

is

0.145 =

7r- +)

ther

a ratio As uming they The

ratio

f 0. 18, 0.86

=

observ d

,-i7(C21

so

p-752 rr+n +

+

the

,-r7(C21

isopn

Ao

7r-

+-

7r-p

t o the

entir ly

exp rim nt

could resolvd consi te

by kinematic

mic

the

exp riment. with

a number

observa l . the

f o overlap ing,

quasifre

Events

mechanis

with

78

Asai Wad .sgiF .sgiF 0

-

O%

Figure and

]9[

both

SAPHIR

A+ A-

3. with

(i.e the neutron with a combination was also ap lied using tag ed f o N * resona ces published. the a r e clear y fo The con lusi oA’ is t o that the A beam en rgy. is sim lar to The results Toki [9]. Like A transit ons t h e o,&N resona ce 4c). The result betw n the above this en rgy, Although the sections are The model deviates from was antic pated,

and

[8],

cros

and without

from the

the

and

ac eptably the

was

whic reproduced becaus

data

obtained

en rgy

data

pion shown taken

prompted

earli

40%

fo absorption into

in

fo

obtained

in by

figures

ac ount

the

by

MeV

further

promine c

the a detail d

quasifre

cros )r72

(T,

cal u tions,

4a)

the

[8].

via

and

cal u tion diagr ms

quite

on

SAPHIR

Althoug an lysi

with

the

4b).

excita on

this

In

sim lar

by model’s ad it on,

by Gomez-T j d r,

greater

iso p n.

with rewol

is

final

=

foundation to

result

experiment,

observ d,

7E

that

the

TAGX

wer

an lysi

TAGX of

at

col ab r tion

the

basi

rapidly

MeV/c

same

befor

the

section

exp riment

> 250

The

at

Oset

N*.

p,

A+ A-

that is exp cted

reaction

d(y,n+n-)n f o Gomez-T jedor,

with

consi ten is

1300

intermediate

contribu ons.

(Bon)

4 a)+b

the

requi s quite

are This

increas

nearly

from

ev nts

5 0821

(TAGX) al.

01

cal u tions

space

.la

te

4 a)+bc

90

(MeV)

the

experiments

ident f .

cal u tion

N*

importance

both be

5 7E result

,E

while

phase

750

hig er

quoted

TAGX types

and

7r+7r-p)n

beam

to

earli

fo fo

A

d(y,

with

contribution

A

quality.

ratio

the

a spectator),

this fo

mechanism at ain g

the

bet er

at

prelim nary

hig er weak

fo

to

phot n

sections

compared

was

700

te

and

en rgy.

710

at

contribution

shown

is shown in figure 3 . Ther si a construc ive interf nce below E-, z 820 VeM and a destructive interf nce si d u e t o t h e change f o igns f o t h e real part fo t h e "N p r o p a g t o r . N * diagram si s m a l , the wol en rgy experimental fo the with its ad it on. describes the phot production data u p t o 7 E = 08 MeV, in a steadily worse man er a t t h e hig er en rgi s. This discrepancy diagrams involg t h e virtual y p meson exchange cur ent,

Bon can

phot n

MeV,

contribution

tif

best

technique

but I t is also

increasing

[7]

Toki

is

Oset

that se n whic and

AN in

be

and

+-

fo

figure

diagrams

cros but such

19

I

74

\ = I

\

A

n

by

Figure such

se

as

4.

Gomez-T jedor,

in

as

that

one,

figure

rec ntly, det ction

experiment the

nuclear

MeV/c are also

ew

that dynamics,

the

tensor

fo

com unity.

fo

fo

diagrams

and

not

not

include .

Toki

include

[9].

include .

play

the

p diagrams

deuteron a more

d)

f I e w compare inde D- s t a e ,

in

diagrams

the

with

can ot

important

contribution

whic

model

including

be

was

fo

negl ct d

the

yd

the intermediate

result negl ct d

at

fo

A+ A-

Schwesingr

+

thes in

as

the

en rgy

thes

reaction meson ,

vector

en rgi s.

et

al.,

Ther

ew

cal u tions, is increas d. thes studies wer extende t o lower en rgy o n 3He by t h e TAGX ol-c Inclusive ,i:(eH3 7r+7r-) data wer obtained from 083 t o 70 eVM inc de t In t h e case f o the lowest en rgy, this is only 50 eVM above the absolute threshold. The det ction f o ad it onal prot ns, whic would have made more exclusiv in n a t u r e , was preclud by p r o t n rangeout in t h e t a r g e t , prot n mo entum det ction threshold. The result are shown in gen ral y consi ten with the deuteron data, after multip cation by 1.5 se that the data are in excs fo the Gomez-T j d r e t a l . predict on by t h e same factor), a iferncd hicw can ot b e explained by t h e i n reaction threshold betw n 2H a n d 3He. Analysi of hig er en rgy data from TAGX is stil underway. e w have se n that A mechanism d o inde play a n ident f abl role in reactions above x 05 MeV, although the importance f o their role has somewhat from the first optim s c expecta ions. Noneth l s , i t would study f o this mechanism can play a role i n our bet er understanding fo number f o topics whic have su tained inter st a s i t touches on a large Thes is ue include t h e role that repulsiv SRC play in s e t i n g the AN + AA proces , t h e interf nce f o N* and p r contributions, and force. to

induced

/ ;

Oset

wer

inclus o

dif er nc

7r+~-p) temper d

wer

[lo].

en rgy.

multiplication

con lusion,

question

expected

03 5, a n d MeV

4d),

the

the

7r+ -

strength AN

sample

this

s i also but also More laboration phot n

the and figure Howevr, (after x 52 3He(y. In 7r a n d be n ap ear nuclear in t h e the the

a).b),c)

08

A

-

-^p

d*1.5

d*1.5

9 with 9 o/w

’N

’N

I

04

.3 W

7 (d*l.5) 8 (d*l.5) 10 ) e H 3 ( Ref. .feR Ref.

o ef.R w Ref.

b 02

0 ’

’ - ’

053

Figure data

and

5.

calculations

The author col aborators work was fo Canada

3He(y,A p)

sup orted

cros

on

over

wishe

to

the

in

(NSERC).

last

thank part

by

years.

’

and the

I t was Natural

at

(after

the

TAGX

a very

’

650

(MeV)

obtained

target

INS

’

05

,E

sections

deuterium

ten

’

054

’

Sciens

’

TAGX

multip cation

enjoyabl

’

057

I ’

850

[lo],

col ab r tion and

Engi e r ng

and by

for valu b e

.1 5 ) .

and

compared

with

their Res arch

role exp rienc .

as

1.

3. 4. 5. 6. 7. 8. 9.

Y. 10.

G.E B. D. A. J.P A. M. Confer c , J.A. D. G .

Schwesing r, Ashery, Ab as, Rah v, Asai, Wad ,

Brown,

Schifer.

Gornez-T j dor,

Wat s.

H.

A.

Toki,

Wirzba,

W.

Weis.

J.P. chifer,S An . J . Phys. G 1 7 (19 ) Comrn. Nucl. Part. et a l . , Phys. Rev. et al., Z . Phys. 34 rep s nti g the SAPHIR Wil iamsburg, Virg n a, E. Oset, et al., Phys. Rev.

A.

G.E.

Rev. Let .

A

L18.

Phys.

C

Toki,

5

Phys.

Phys. Part.

Nucl. (19 )

6

(19 3)

H.

Wirzba,

Brown,

col ab r tion, 196 (19 7)

14

Sci. (1985)

Phys.

63

132B

1 8B

(1986)

Particles

(unpublished). 1832.

(1982)

(1983)

269.

207.

39.

15. 1279.

35.

Let .

Let .

Let .

346B

and (19 5)

Nuclei

International 240.

host Council

REF NCES 2.

the

This

and

K.

Hadron

’

20

Nuclear and

Maruym

and

Elsevir

The

Scien

neutral

.T-1

fo

+oE proces = -

the

+-n

.1

INTRODUCTION

stracted and vector cros ment ChPT cal u tion

yp diferncs

The be results

19 4,

Fuchs

meson sections with

Even

caused

pointed

the exp rimental contributions

the al.

near

those

can ot

perfo med cal u ted situation,

betw n

ifm-’

=

+oE

real, -0.87

an can

MI+

is x

the

10-3mLi.

contex

7r+

near

out cros

[4] result

diagr ms

that

section wer

ag in

with numerical

a yek

LET

converg

threshold

Such

mo entum

Eo+(yp

Korea

to

extract

chiral

Eo+

to

prot n

near on

imples

ac ount.

evn

a proces

be

is

left

in in

thres old

that

contribu on

rep oduce

el ctri

measur

whet r below

the

wol of

is exprsd

amplitude

drew

en rgy

conserv d

PCA .

consi ten ly

be with total

and

are

thres old as

7r+

charge

in

[6].

os

the

the

near

exchang

[7]

far,

rescat-

axi l

at

pro e ly

Howevr,

the

sub-

thres old

LET

dif enr t al go d

fi agre -

the the

becaus proces , fo

becaus

mas (1)

pion-ucle below

are

cur ent a reason,

’rn

is t h e

vector

at-

such

should

amplitude

the the result

trem ndous theorem(LET) For

the result

Their theory(ChPT)

Eo+ for

.ylwo s

our

dipole

to

by t a k i n g is edl that proces . Our = -2.15 x qk$;m3-01 frame f o cal u tion.

this

MI-

the parti l y a break

ac ur y.

perturbation to

the

cal u ted conlusi

and

resto d

p-wave

predict on

A role

is l ew

l ew

Korea

be n

a yek

pion into exp riment

520-714,

have

t-chan el.

the a pos ib l ty is based

LET

the improved

question

on

the

could

the

--+ )

than

fo

the

Eo+(yp 0.172fm

x qk$;m3-01

fo

[2,3].

7ro)p

fo plays

7.56

rap.

and

p(y,

taken

by

exact

120-749, Naju

for

=

the

a break

contribute

pro) = is l a r g e i.e

hypot esi

the Since

pro) +

+

Seoul

model

thres old

+-n

nn-+

u(nr+

0.19 makes

pole

thres old

lo p

-+

x 1;m3-01

Ef+

[5]

i q u(nn-+

26.

[l], a sen ation

to al

make the

fo this

in

the

phot production in

down.

prot n

Universty,

the PCA

pion

et

n+-n =

wher

broken

ew

from

that

4

Et+

hypot esi

amplitudes

The

physic t

Universty, Dongshi

in

the

Jeongb Yonsei

below

x 10-3m;:,

fo

on

T.

MI+

ac ount

81

resvd.

Physic ,

1.23

threshold.

neutral

In

and

into

Probes

rights Al

Physic , of

The

Electromagni (Editors)

phot production M.

bDepartment

tention might (PCA ) the

B.V

and

"Department

Eo+

htiw

onukO

pion

Cheon"

meson tering

Physic H.

-+

the

by

pro) 7r+

thres old.

scat ering one

orde

This

length, fo

magneti ude imag n ry

Eo+(yp

) ’ n n and mo entum

=

+-

q =

(2)

82

Henc, tum Notice proces. defin t

a question below

that

It a.nswer

arise

thres old

the

si

to

pro ag tion very

whet r inter s g

the

can

rescat ing

contribute

particle

to

question.

to

si car ying

an lyse

of

the

proces,

the

pion a real

carefuly

i.e

mo entu

the

car ying

the

an

real

imag n ry in

exp rim ntal

part

of

us al

rescat ering

result

moen-

amplitude. to

dnif

a

CAL U ATION

2.

si given

The

LET

predict on

as

Eo+(yp wher

the

pro)

+-

p

938. MeV. the Ther fo , Born

term

. The

and

us

the consider

Since take

wher

the has

A contrib ons

MfLet

in

be n

of

evalu te

The

and genral

The

=

(p2

pion

and Ai,

-

form

yb

pion

en rgy a set

mo enta.

estima ed

er w

as + f M ni b o t h

cal u ted

the

sevral

estima ed

amplitude

the to in

anom ly

our

disperon play

e2/4n

authors cal u tion.

an

si

cal u ted

=

the

=

theory

[9]

due

[lo].

of

linear

the Each

(3 )equations

contribu

the

1.79, result

to

the

and

to meson

vector

Althoug

4,

the

the the

exchang

rank

on-shel

to

be -6.31 =

BL

exp rim ntal s i describ

coupling

saw

The

x 10-3m;ikq

the

pole

us al y

result ,

yb

phot n

.]8[

x lOV3m;:kq

negl ct d.

model

term

amplitude,

resonac. as

,F

has we

polariz t n frame

=

On

x 10-3m;i.

4.17

using

M

and

theory

=

vector

(3) cal u tion.

+0.15

the

centr-ofmas

Nn

135MeV =

M&

term

si t h e

ip

of

-fM

are meson

coupling

rep oduc

m,o

fo

thres old

x 10-3m;i,

x 10-3m;i.

framewok

at

vector is

given

in

k]Fz+i(a.I;)(i.G)F3+i(g’~)(El.$)F4

(~.G)o.[Elx

to

in

=

reaction

-2.7 =

u-chanels

, tensor role

Vector

amplitude

up

x 10-3m;:kq

and

s-

-0.72 in

the

pro

+-

O(p3)] Pct

si

l ehs-f o

3.1

+

K ~ )

137,

eq.(2)

+fE

=

[8,10 ]

importan

+ in

term

phot r duction

fo

given

py

rof

1 -p2(3 2

pseudotnr

+ the

of

yb

F=Z(O.E)FI

rof

amplitudes

si a n t i s y m e t r i c

E~,,,~

t

ew

x .qk:;m3-01

it si expctd it into ac ount

0. 8, =

amplitudes

+

[-p

model,

be n

chan el

dipole

Ef+

rescat ering

dipole

elctri

f2/4n

amplitude

1.84

=

t-

quark

the

(4nm,+)-lef =

m,o/M =

basi Magnetic

of

the (5)

Her ,

can

be

k and conetd

are

the

to

unit

the

vectors

invar t

of

the amplitudes

phot n

38

wher

+

(rn

in t h e gPv/4r coupling

close

whic

+

to

imples

det rmine

yb

of those the above wnyg = si t o sevig a gyKp =

+{EA

the

oT

contribu ons

-0.983

vert x

Notice show

result. si pd contribut ons in

compared

With

+

the

are

pd,

to

other

thes

AEi+

the

&.&

=

must defict values,

+

(-0.62 =

if

si

for value us

thes

&

r(p0

gwr/v

whic with

mb), (m2 ri.4/TLg

sevig

i.e

2.38)

has

defict and

ratio consta

and

0. 14nr

elihw

amplitude

conlude 1.76

=

[13], si

a large are

10. 06nm.

contribu on the

Apd gynP

oT negatv

at

thres old

are

being

Our at

+0. 25nm, to

than The

value

be

estima es

compensat

"’7) gynw

of

0.5, The

data very

whic

i.e (10)

RESULT

3.

The

evaw-s

Ehh, =

Mi-

M1+

+oE

amplitude

+ E,$F

-2. 7 +3.1 -6.31

Born

for

AEr+

+4.17 +1.84

neutral

+ (-2.7

=

A(123 )

the

0

(p,w)

0.26 2.3

1.76

pion 1.76)

phot r duc ion

at

x :im3-01

Rescat . 0.72

0

0

=

-2.15

+7.56

-1.23

-0.51

thres old

yields

Sum

x 10-3mi .

1

Exp. -1.32 +7.41 -3.59

(I)

)1 (

hO.l

I

Exp. -1.3 IM 10.2 =

)1 (

80. f

f 0.15

be i.e

dpA

=

the

this The

as

x .:im3-01

=

=

might

least,

negativ ,

1. 2,

at

mo ent. defict

=

6.1

D,

* =

+-

3.18

=

This [13,4].

consta

er o .

(0.067f0.0 7)MeV

undet rmined

magnetic

smaler

gwT

=

r(w

result

0.1 =

10. 9,

=

=

w

and coupling

The

"-7)

cur ents have

(mi/2W,)

Vpg/Tpg

whic

rather

+

f 1.5, T : g

gwv and

widths

=

rof

ew ew

x 10-3mi

2.4, =

of

yrw

:pA sign

0.1 =

lwr?yg/ps I deut ron

The

8.1 =

+-

the

si ositvep = +0. 14nml Thus, the AEr+

find

decay

r(p-

the

coupling

a positve

the

:m =

q2)lI2.

induce

TOY)

t-

[13],

C

+

f 0. 3 )MeV.

lwr?yg/p, l

yrp

Ap:

ew

[12]

2.1,

+ =

si in

the

Apd

as

(0.18

examin

h0. 19nm

f0.013nm. =

find =

whic have

hand,

ew

evalu t d

of let from

A&

ew

data precison

Their sign

sign ,

0.843nm =

result

Their

The

20.5

roy) ratio

-+

that the a bet er

their

know

are

Ez

and

=

Her,

gYTP,

r(p0

f0.0983.

=

On

and

egy?rv/m,o(m~o k2)l 2 =

+ g&/4~

16.05 and

=

f0.130.

of

defict

reason bl

=

Xv

(m2 enpircaly

and

gynw

value

AE" =

gpT

=

are

0.6

&

gynp of .3 decay gyKp SU(3)

neglct

f0.31 .

large

El

and

constants, f 0. 42)MeV and result "-7

(0.71 10.313 SU(3)

stage. exp rimental caused

0.5 =

2.63

p

m,+/(8rWs), with =

NNV

-

QpV

for

5

E,)’I2

84

Eo+

The amplitude yp -+ 7r+n I t si obvi us amplitude by t h e dot ed

E;

0

(7) Thus,

and

near tering rescat ering

7r+

(8).

the

defin

lM taken

values

+1E3 =

I!41

proces ,

result

the

The

from

proces

resp ctiv ly.

The

vector

are

for

solid below

curve

taking

begin g

does

taking i t yields

15 0

dipole

si

not

ac ount

agre

ac ount

shown fo

the

fo the a dot-dashed the experimental

by

with

rescat ering

rescat ering

curve

result.

proc es

in

proces ,

Fig.1

The

is is shown

amplitude

rescat ering 5.

+

and

Experim n-

meson

ML

the

and

cros

the

- Ml-. dot ed

ob-

the dipole

Adl+ x

threshold.

thes

with

2.

dot ed resp ctiv ly.

Total the the

cusp

s-wave

refs.

3,

2,

amplitudes

10-3m;$kq

cros

curves

and

amplitudes

efct

Experimental

The contribution

MK

be =

found

The

obtained due dashed

to

the

data

5. can

are

sections.

are

as

evaluated 2.3

curve are

10-3m;$kq. x

without

solid rescat-

rep-

with

curves

result

cal u ted figures,

are The

the

taken

with

Eqs.

x 10-~~;;kq.

This

section

7 ~ +

to

-2.15 =

jFrom

0.26 =

magnetic

M1+

Figure and and tering, res nt rescat ering. from

curve

-1vi total

1

ampli-

ref.

the

the

without

(f,i2)

dashed

x 10-~~;3~,

2 show

and

kq

dot-dashed

Eo+

with

amplitude.

fo

The

The

the

and

the

x 10-~ ; :,

32.1-

MI.

threshold.

total

7.56

threshold.

without

Fig.1,

O

are

the are

in

dot-dashed in

=

Electromagnetic and

.1 Eo+ curves without

=

Figure

E&

threshold

0.05

results

M~+ eW

+

near

mentio ed

the threshold

at

curve

1

the

Contributions

TOP,

that

+oE

;E =

Figure tudes, dot ed tained below repres nts tal

-+

(13) is in with obtained one dashed

Fig.

1 with

thes may

without curve

confirm

a dashed

el ctromagnetic

and in

Fig.

the

curve. with the exist nce 2 is t h e

amplitude s-wave

rescat-

fo

the

85

01

0

2

Q

L

40 02

9

PION

Figure tained lated from contribut on with improved

of

The curve can solid ew Althoug pres nt domina ce. the

the

Figure solid

rec nt

rep sent

se

rho

meson, amplitude

’ =" + L O E This

value

3 hows ac ur y curve

cal u tion,

ew

the

swoh dot ed Since

have

f

si somewhat

the the

shifted

the

result

AEr+

Ehh+

ef ct diferntal

and

gpT

i.e Since

the

curves dot ed =

with

9.73

= =

saw

curves

+

AEr+(-2. 7 esolc

0.93) to

downar

rof

Fuchs

the used

case from

given

dot ed

151.

result empircal

7E

exp rim ntal

=

x i;m3-01

3.7

woleb

15 .7MeV value

value based in

are

rof our

while T+

much

bet er

the

gpT/gpV

on previous

the

7r+

and

Ther fo ,

152. MeV =

tensor

the

result the

thres old.

su(3)

x 10-3mi .

-1.34

consi te

data previous

the

taken

are

the ]5[

obcalu-

result

woleb only

are

are

data

with

=

smal

cures curves

Our

al. contribu on,

ap e rs fo

gpT/gpV

eq.(l2).

proces.

et

contribu

=

in

recnt

the rather

0.93 =

and dashe

Experim ntal

compared

her

x 10-3mi

that

with

rescat ing exp rim ntal

from

AE&

yb

the the

discue

The

(14).

rs cat ering

rescat ering

solid

eq.

the

an lysi

+

&EA

in

section

with

evalu t d evalu t d

to

withou

the

The

rescat ing.

obtained cros

agre

16.05 previous

due globay

result

section.

the given

data

rescat ering

our

gpT

cros

with

cusp

any used

and

amplitude

the

exp rim ntal

the

not

with

with

that

curves.

do

ref.[5]

Diferntial

.3 withou

1"I,,e ANGLE

cal u tion,

[5],

whic

[2].

dot ed thres old, 6.1

eW

than

coupling

the

in

the

vector

(14)

it may

be

sup o ed

that

86

if gpT proces threshold Howev r, a s si se n either. =

below

9.73

in

is u s e d , the

en rgy the

the can

improved

Fig.

7r+

reason bly

3.

experimental

threshold. data

Agre m nt

at

with

be

7E

result

Inde d, reproduced. =

15 .7MeV

the

can

the

dif er nt al

f o +oE

data

be The

explained result

and

cros

152.5MeV

shown

without are

shown

in

Fig.2

the

sections can

by

not

could

be not

dashed

rescat ering

up

to

reproduced, be

the curves.

+r

sati f ed

CON LUSI

4.

10-3m;ikq

Our

results

pion car ying a s a physical the rec nt remains

are

at

+oE

the

an

valid.

imaginary

meani gful

experimental

= 7r+

-1.23

threshold.

x 10-3m;i,

proces .

results

mo entum

eW

are below

Our consi ten

are

MI+ led

=

to

a con lusi

the

pres nt

7.56

x 10-3m;ikq

threshold

7r+

investiga on

with

that

the

LET

and

leads

and

the

can

play the

Mirescat ering

to

PCAC

=

important a con lusi

REF NC S

hypot esi

2. 3.

.1

4.

5. 6. 7. 8. 9.

10. .1 12. 13. 14.

P. d e R . Beck J. C. B. G . M . Fuchs V. Bernard, A. N . I . Blomqvist J . Wes F. A . T . Schafer T . Ericson R. J . M. Chemtob,

Baenst, Bergstrom Yu,

et et

Il-T.

Adler,

and

B. and and

Phys.

Phys.

Phys. Cheon

al., N.

Kam l, Ber nds,

Nucl.

al.,

Kaiser

Phys.

and

A.

E.

Zumino, W. W.

et

al.,

Phys. Rev. J . Laget, Don achie Weis , Weis , Rev. J . Moniz

B24,

Rev. and Let . and

63

Let .

Phys.

Rev. M.

U.

Let .

Nucl. 14 ,

T.

B368,

Meis n r,

63,

and Pion

and

149 ( 6 ). M.

Phys.

(1970).

02

D. L. Nuclei , Rho,

A531,

(19 0). Phys.

Z. A280,

37B,

and

R1052( 9 6). J.

(19 6).

2346(198 ).

Phys.

Let .

184

C53,

Jeong,

Nucl.

Phys.

65,

Weav r,

Phys.

SOC.

95

Phys.

Japan

C70,

483

405

(197 ).

Clarendo Rev.

87

(19 4).

(19 6).

(197 ). Nucl.

520

63,

Phys.

(19 ).

B4,

103

Pres , C10,

34

Oxford (1974).

(1967). 198.

-2.15

of

roles

the that

x

Hadron K.

’

and Maruym

02

Nuclear and

Elsevir

Scien

Phot neutron Compton Toykaw,

305-86,

Electromagni

lA

Probes resvd.

rights

measurem nt

laser H.

Physic ,

rate

Univers ty,

yb

eB’

Yam gat

fo

means

and

Okamot

M.

invers

Ohta

with

Sak i,

the

MeV

step

Result

data

Higash n da,

Osak

wer of

taken

for

a-proces , with

measur d phot n other

Japan

1-4, Umezon

for

source.

the

Kobe

59-870,

Labor t y,

sections first

8-91,

1-2,

, Electro echni al

Div.

cros a laser- ct on f o the

supernovae.

T.

Gakuencho

Japan

using

phot ns

Akimune,

Kona

Radiation

on

Ohgakic

Univers ty,

Phot neutron 4 . 0 VeM the reaction core- l aps in c o m p a r i s o n

87

Yonezaw ,

H.

fo

Japan

’Quantum Ibar ki

(Editors)

section fo

and

Pref cture

eB’

Thes

Q(m, 5/2-, phot n

1/2+,

y)’Be.

in 1/2-,

the cros and

source .

en rgy in

Tsuk ba, range

section a neutrino-driven 5/2+

from

are

sta es

1.8

rel vant

are

to to fo

wind

pres nt d

INTRODUCTION

1.

two

B.V

Y.

bOsak

the proces d folwed than nuclei

htiw

cros

Utsunomiya, Fujish ro

De p a r t m e n t 658-01,

O h 0

scat ering

H. M. H. a

Physic

H.

The

neutrino-driven

r-p oces the

by

into

[l].

9Be

the

triple beyond is a losey-bund

In

j6Fe

Q

’Be(a,

proces . for

through

wind

this

formed

rapidly Q(Q

n)12C. r-p oces .

This sub eq nt

The

n,

in

expandi g sequ nc

core-laps

enviro ment,

yb reaction

of

supernova bridg n

C"

network

production

mas

n-

gaps

consti uents

+

alone

+

can

nuclear

form

A

proce ds

is consider

sy tem consi t g f o two a’s a bound sy tem. The lifet m s x x sec, respctivly. Thre adj cent ecs and 0.97 Q n , at 1.6 5 eVM for 8Be n and a t 2.467 MeV MeV for Q the lifet m s, the synthesi f o 9Be is consider t o proce d more than through jHe in two ucesiv binary proces. The ternary a minor role. Resona c near thes thres old det rmine the Resona c par met rs f o thes sta es can be obtained yb phot dis ntegra ing Previously, phot neutron cros section for e B ’ wer measur d kinds f o real phot n sources, Brems trahlung and radio ct ve measur ments with a phot n difernc method ackedl great ac ur y resoluti n [2]. Measur ments with radio ct ve isot pes (24Na, Io5Ru, lZ4Sb, 142, Pr and 20GBi) wer lim ted below 2.75 VeM eB’

may

and

and thres old

+

domina tly rate isot pes. ,1A"

.18-3[

be

a-rich

an

ideal site orf material si first 5 and 8 , whic si more ficently t o produce eds

=

a neutron. 5He

fo for

and

proces

fo

near

the thres old

38Cl,

exist

+

5He

Low-lying

due

eB’

Non In

Q.

is ikely eB’ Brems trahlung to j8Co,

through ’Be. po r

at

1.573

view to

synthesi .

any

fo

are

play

using G5Ni,

8Be

1.1

of

two en rgy sta es

8 Y,

in

8

eB

er w

lated data

also

the for

al

first resonac

in

state states

EXP RIMENTAL

2. 2.1.

y-ra Invers

TERAS in

the

rof cm

ratio, grated

A

scat ering only

thres old

413

light

VeM

15 in

Neutron minutes producing

length). deut rons

laser

10

% to

col imated

colisn

mCi I t saw

the

and

scat ering

linear y

throug

into

point 9Be er w

the

time to at

at

24.1

Background

the the

40K with

range

polarized

optical

yrev

[9,10].

.ylkaew

(1/2+,

fo

9 .5

neutron er w

The to al

with n

the det c ion

24Na mixed

The

4572

thermal 24Na

and

in

the

ac ur y

averg

,rev woH

No

5/2-,

with Vek produce

beta-d c y

of

enrichm t

two Neutron

as cmHg

single

virtual

measur nt 5/2+).

1/2-,

2 cm3

length) moderati n

directly

of

and of

65 a time- nd p t

phot ns

po uprovide

saw D20 transit on Vek

to

phot n

in

at

neutro s.

cm

in

4+

alumin

yb Resarch to

state

Contribu ons

diamet r) in

DC-beam

2+

in

contai er

pulse the

car ied

measur nt

with

at

polyethn

saw

(2

frequncy

separ tely

sample

a 9.4 Thes f o other

measur d

and pasing varied

MeV. m

y

from

a moderati n

rof

saw

in

saw a minor

with

diamet r

x

y rays sta es

6

phot n

befor

a DC and

agred

of

in

taken

(IkHz)

Kyot

%

ring mea-

the det rmined

of

a

2.5

cube.

out

measur d

mc

1 zHk

a con e tri

diamet r

mg

5.

a luxf er w

-ueN

made

saw

LEMPS

yb saw

4.0

stor-

ir ad te . D N :06-4358

in

that er w

-

l show

(2 obtained

a 05 Insti ute

transit on.

saw

enrgy

en rgy-calib ted

6oC .

in

comp ne t,

Reactor 24Mg

enrgy

cm polyethn

from

at VeM

saw

the with

pro e ti s

produce kcolb of

beam

source,

1.8

peak

the Fig.

er w

neutrons

Pb

fo

a 03

er w per

ir ad ting

the

source

in

spectrum obtained

saw

Electron y-ra

det c or

and

made

horizntaly,

spectra

pulsed-

the

(MITSUB H

time

module.

phot ns measur nt

an

the

of

thick

operat d also

in typical

beam

saw

range

enrgy

and

a BGO

Pile-up

dnuorgkcab the

counters emb d

[12].

el ctrons

quasi-mon chr ati

phot n

beam

The

saw

mc

phot ns.

CAT

phot ns

of 5 .%

hours)

in

verticaly

with

number a ingles

(2.5

A ful a standard

VeM

sy tem

enrgy

a 02

produces

%. light

depolariz .

laser as

relativ s c wen

laser the

type.

line.

fo

562

with

in

on

(ETL)

a encil-kp of a w e f

spectrom

3FB

ORTEC

neutrons,

caled

l ew

each

result

neutrons

Unpolarized

This

as

The

and coaxil

06

[l ].

y rays

Indep t

15

y rays

light.

incdet

Labor t y VeM

used.

diamet r

esu

neutrons

The

saw

beam

number

time.

1T802

ef ctiv an

of

el ctrons

%

ycnei f (half-ie

with

four

with

dnuorge of

04 si vailbe resolutin

and

measur nt.

det c ed

end

1 to

in

axis.

with

phot ns

elmnt

produce

det c ion

laser

anti-Compt n

nm)

to

det c or

located,

1 kHz. spectra The

acquis t on

an

cm

beam

enrgy

2 m

betwn

of

rod x

1053 an

VeM

source),

and

=

574

pure-G source

from with

(A

neutron of

Electro hni al

range phot n

VeM

invest ga d

Nd:YLF

2.16

of enrgy

phot ns/ ec m 2

wer

production

Compt n

a 15 cm3 natural A 4 cm thick trons er w measur d cm in diamet r The 3FB counters a t 7.5 cm from sured in l ms time distr bu ion. contribut on Incide t phot ns length) placed beam pulsed from the pile-u with a DC b e a m . and the data beam, in whic after each measur nt. t o each other 2.2.

el ctron

(1/2+) near

METHOD

age ring y rays (laser- ct on of l o 4 previously A produce polarized from rays head-on with with

versity.

invest ga d excit d

branchi g

NaOH

in

dis nte-

-inU

24Mg

x

4

89

lo:

*t

11 I

Figure

about time- nd pe ntly inter s .

to

The

neutron

bath flux (MITSUB H neutrons ground Time of production The saw coverd eficny uncertain y of t h e Fig. The MeV. MCNP

saw

method

had

neutrons

during

counters. smal The

thus

stem d

2 show

en rgy [15].

saw

The

evif

The

saw

also

the mc

saw

placed contribut on

to al

done

measur d

dep n c

each

and

ycnei f

with

17.5 the

562

sy tema ic

1.7

% the

of

in

det rminat on

the ycnei f e

a 25Cf

RESULT

3.

Cros

section

er w

obtained

with

a formula

in

the

the x

a t t h e cent r 03 second, of ackgroundb Vek neutrons

with of

same

saw

2.83

that

of

neutron at

mc with

rof

time dist ngu hed

becaus

Vek

be

rof 1 %

placed

to

to

rof ycnei f

562

The

neutrons

cleary

saw The

distr bution

1 ms.

are

measur nt

from

counter

the

Background

be n

measur d

the times,

2.5

time

si

neglctd

fo source

from

det rmined

det rmined 3FB

scale

er w

er w source

Ful

p sec.

ND852-60).

separ tely

neutron

perfo m d

041

inte s y [13].

measur d

elaps d

ycnei f

production

absolute

Moderat.in

.1

cube.

i

Number

Chan el

len

’"1

l

" " " " ’

" " ’

cor e t d

smal centr 2.5

calibr t on

lo3

standard

counter

of

source

ar ived

cm

step

det c or saw

esohw

cal u ted

der voc

from

phot neu rons

saw

of

graphite

of

with

the The

saw

as averg

0. 9

moderation

a polyeth3FB

si

counters of

ratios. liter smal

with

water a 1.5

cm3

counter elip at yb a 5 m ources inte s y

det c or.

&

the

at

det rmined

a 04

bare

of

in

rof

branchi g source

for. counts/sec/4~. t h e neutron with wot neutrons saw 1.67 in neutron

er o neutron

neutrons

consta

3FB very

counti g,

source a functio

counters

% per inte s y.

with

neutron

ETL

the

bath.

3FB

thick

3FB of

a Monte

counter. in

neutron

cadmiu .

enrgy

counter thermal Back-

the counti g

and

The

5 %

[14].

at

A neutron smal .

rof

water

Neutron

det c ion

time two

CdThe

calibr t on enrgy. Carlo

si .352 code

90

12 ,

1 8

.

.

.

fo

wher the det ction target.

wher material. that (solid excita on-e rgy hig -en rgy 1.6 5-MeV flux spread Cur ently, (^/-decay

Pin

BGO

eficny.

p

Fig.

2. 24NaOH

the

+

eficny

is t h e det ctor,

is t h e The 3 show

Neutron

The

number

total at enuation

Nt

was

is t h e A cor e tion

y-at enuation

D2O

fo

cal u ted

and

neutrons number

coefint

.

.

.

.

.

.

.

01

was

det cted,

factor,

coefint

was

.

.

.

MCNP

.

.

target

.

02

0 51

neutron

the

nuclei

f , was

0 52

a functio

det rmined

en rgy

MCNP

is

,N

9Be,

and

from

cm2,

rof

[16].

dep ndence

Monte

the

per

ne d

in

taken

.

Cal.

as The

.

Carlo

eficny with

fo

.

E (keV)

exp rimental y

25 Cf.

.

Monte

05

det ction eficny

.

+ D2 0

24NaOH

0

Figure en rgy.

.

number the

t is t h e

with

fo

neutron sources

Carlo

fo

code.

fo

&,(En)

and measurem nt

length

y rays

fo

is t h e with

the

inc de t

neutron

eB’

on a thick

target

a function f o y en rgy. Note with those for polarized ones cir les) within sta istical The pres nt measur ment ful y coverd the range f o thre resona ces (5/2-, 1/2-. 5/2+), hilew i t cover d only a tail fo the first excit d state (1/2+). This si becaus as ap roaching t o the threshold, it b e c a m e difcult t o ac ur tely evalu te what fraction f o t h e y-ray lay a b o v e t h e neutron threshold. A Monte Carlo cal u tion f o t h e asym etric en rgy f o LEMPS may help de uc the nec s ary y flux. This wil b e done in t h e fut re. a least- quare itf t o t h e data si i n prog es t o de uc resona ce par met rs widths etc.) towards a n evalu tion fo the rel vant reaction rate. results

for

measur d unpolarized

phot neutron

y

rays uncertain es.

(open

cros

cir les)

sections

agre

as

91 /-

2.0

t 1.5

tnes rP

I

stlu er )dezira1opnu(stl er Presnt

o

orihs juF B.Hamersh

+

i

l es uR.B J.HGibons W.John nosb kaJ o A N

.....

,/

/

,,

(polarized) te

al.

te

aL(1962)

RI

te )3591(. a (1948) t e al.(195)

.la

te te

(1982)

RI

(196) al.

RI

RI

RI

s merB

/

,8

.. O O i Y

’ ’

1.5

’

2.0

"

"

’

2.5

’ ’

E

Figure results radio ct ve

the

Phot neutron

prec ding

isot pes

are

cros measur ments also

3.0

"

" "

’

3.5

"

’

’

4.0

’

’ "

4.5

(MeV) r

section

for with

shown.

gBe.

For

Brems trahlung

comparison,

and

ACKNOWLEDGMENT

4.

for

3. fo

"

eW Ogaw

are his

techni al

(Electro echni al standard Foundat

indebted (Kinki

Univers ty)

as i tance

Mr.

K. for

Laboratory) pile.

graphite

ion.

to

Okamot the

in

This

his

ir adiation help for

work

was

(Res arch his

NaOH

fo

in run ing co peration sup orted

Reactor the

in

yb

MCNP the

Insti ute

with the

det ctor

Japan

thermal

fo code, Private

REF NC S .1 2. 3. 4. 5. 6. 7. 8. 9.

S.E. M.K. B. B. J.H. W. M.

Wosley Rus el Hamer sh John Fujish ro Fujish ro

M.

10.

H.-G G.

Kuechl r

and

Jakobson, Gib ons

e t al., and

Clerc

et J.M.

and

e t al., e t al., e t al., e t al.,

Phys. Phys.

R.D. C.

al.,

Pros e , Nucl.

Z.

Rev. Phys.

Can. Can. Phys.

Hof man, Rev. Kimbal ,

123 73

(1948)

Rev.

Phys. J . Phys. J . Phys. Phys.

(196 ) 14

Astrophys. 54.

Phys. Rev.

A326

60 A120

(195 ) (1982) (1983)

61 (1987)

J . 395 29.

Rev. 163

13 9.

(1968) 47.

90 (1967)

(1953)

(19 2)

1672.

1579. 41.

20.

958.

1063.

and calibr t on

neutrons,

Kyot

Univers ty)

Schol

to

Dr .

to Prom tion

K. with

Mr.

Kudo

Y. the

92

.1 12. 13. 14. 15.

16.

H.

H. Experim ntal weN Y. J.F 4B, Engi e r Blizard, (Springe -V la

Toykaw

Ohgaki York,

Inoue Las

Briesm ter,

e t a l . , Nucl. e t al., IE Tran. nuclear hysic,p YN 1978) p . .5 4 e t a l . , Bul . Electro ech. MCNP, Alamos Nation l Compendium A.B Chilton, M. weN kroY

Instr.

A Gen ral Labor t y, on Radi t on Grotenhuis, Inc.

Nucl.

and Sci.

.loV

1968)

Lab.

Methods 2,

38

Monte

edit 31 197. p.

A.

in (19)

(1967) Schieldng, 173.

Honig,

yb

Carlo

Phys.

Res.

.683

E. 60.

2 4A

Segr

(John,

N-Particle Th.

(19 )

95.

&

Wiley Transport

.loV

A.

,1 edit Jaeg r,

Son,

Inc.,

by

Code, and

R.G

H.

Version Jaeg r,

Eisenlohr

E.P

Hadron

K.

’

dna

20

Maruym

Nuclear

dna

Elsevir

Nuclear

Scien

B.V


Al

Probes

sthgir

resvd.

Nuclear

A odelm t o cal u ate The multis ep a nucle s, excit d residual nism . Comp ne ts exp rimental Synchrot n

of

Res arch,

The

el ctromagne ic

the

model

(2)

and

inclusve intra uclear

includes

nuclei

data

CERN

describ of

obtained

spectrum

wher x =

A,

*Sup orted te-mail:

=

to RHIC

play

of

the

model

phot ns

at

theor tical an

v/c

%

,1

contai s

of

ultra el tiv s c

>

fine by:

by

INTAS

data

The

al

spends

)1

structure

felowship

mean

yb

with

heavy-ion

coliders

obtained

models

role of

equivalnt

of

Scien,

2137

relativ s c

heavy and

produce

double

deif r v

yb

nois f phot ns

respctivly.

in

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dis oc at n

a short

frequncis

constant,

number

68- 9 FSY

colisn proces

of

ielcun

of

moving

time

up

to phot nuclear

KO

at

At

the

and

on

5 1/R2,

Q2

to

phot ns

the

near

proces.

the maxiu

absor ed

1K

of

si may

phot ns.

a uclesn Due real, in exprimnts

almost describng

nucles the

char te is c

of

of

ions such

hadrons

virtual

and

heavy

multifrag en tio

Rus ia

whic

interac o s

and

and

comparisn

,wocs M makes phot n

(3) of

absorpti n

sta i cal

cal u tion ions

at

it posible pres nt d.

si

yb

decay result

mecha-

KE -Tan shi

of

with

MODEL

dleif phot ns.

are

single of

evapor ti n,

er w

monergtic

ac el r to ,

[2,3].

el ctromagne ic

(y

a si t h e

UR.KSTIORT.RNI.02LA@VONHCINEHSP

phot ns

reaction

the

)1(

excita on

LHC method Coulmb

Academy

THE

important

equivalnt

exclusiv

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SP

Coul mb

an

and

such

E,b/(yp). si defin

interac o

and

OF relativ s c

of Lorentz-bsd the absorption the nucle s, phot nuclear ap ropriate the pro e ti s Since

virtual

Rus ian

DE S C R I P T O N

exp ct d coliders,

yb

* t

for

.1

93

induce

Pshenicov"

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P

with Okuno

dis ntegration I.A

Weizsackr-lm

Physic

H.

a nwo k-l e ultra e iv st c

be

Acording

the cohernt with

colisn

the

impact

are

phenom describ

in

to partne

heavy

the

this

nature of R si t h e uclearn real monergtic reactions aym par met r

colisn

partner,

enrgy

the

yb

modife

the

may

phot n

radius.

-

virtual l/At

partner

emison phot ns

used

b with the

les B

the

be

be

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colisn

framewok

method

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functio s

at impact

treated

of

si

wen

the yb

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the

It

and

predict

-

phot n

of

velocity

y/R:

mas

and

as

94

plicty

wher

(E,)

O A ~

from

the

As uming

phot neu ron rn(b),

proces

with

si the Eq.(2), rof

[4]

the

The dis ntegration to diferntal other ELectromagn ic the cleon nary menta ion ceds (SM ) The fragments decay mechanis 2.

place

)lE( ’!f values

be

cal u ted

In intra uclear

ro

nois f

competi on

fo

[6].

yN d2a/dRdP old [5]. in Ref.

"’,f

7rN,

+-

The ]5[

the

nuclear

of

fo with

spectra

yN

also

are

chanel

for

i :

functio s:

N(2) E1,

creat d

-+

avilbe

E2) single

defin

E2)

model.

produce

fast

and

when

and

light

the via residual of

si

evapor ti n

and

mechanis

=

fo

and

produce

[6]

at

the

describ

n

coalesn

the

cal u tion

excita on

fast

and set

particles of

y(np) have exp rim ntal

@,

of

yb

with

the

may s i lsoa of fast

take

schem

describ

of

+ T-,

and np

to 7 and

of

place

nucleos

A 5 16

yam

the

and

mean second-r

multi-

b)N(E2, ratios

the

enrgy

starting

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include Monte

with first-

interac ion.

with

si treated

for may

transve are

sta i cal

7

rapid ty,

the after nucleos

stage

obtained

the

absorpti n,

LIGHTES Due

complex

exprsion

the

a later

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E7,

on

branchi g

phot n

rof

nois f

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Simlar

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code

AND

phot n phot absorption. Nr72

as double

particles

sevral (RELDIS) particles the evapor ti n f!2)

and

section

absorpti n

cal u ted

spectral

NUCLEONS

the

pions

multis ep

nuclei

evapor ti n

details

on

the

of

[5],

pair

OF in

multipho n

phot n

and

Other

EMIS ON Dependig

of

fi(2) E1,

dominates elis f

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i in our

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section

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7 MeV.

N

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b),

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ro

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proces 3 - 4 eV/nucloM [6]. roF

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bmtn

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to

rof

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vari bles.

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at

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single

1

bmtn

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ap ro iate

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the

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phot n and

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in

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Fermi

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rof

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found

consider

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into

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simulation, absorpti n

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b).

ro

4He

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and

namely,

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E*,

the

lightes

break-up

[4,5 8].

fison.

the

the shapes data

cal u ted p predict

contribu s

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number, above at

041

yb

the

difernt double

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the

pion

fo

sevral model

5 01

diferntal

proces

[7].

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production

er w VeM

take mechanis: compared

spectra thres includ g

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model

FRAGMENTS mas

the

59

the descript on colisn

data

obtained

Fast

hadrons

the

hig

en rgy nucleos

of si e m i t d

angles.

isotr p c.

Becaus

deut ron

si

Y-2

>

the

obtained.

after

the

nucleos

bar ie the

phot n yb in

phot abs r ion

1.3-GeV

means light

spectra

Electron absorpti n

leading

of nuclei

is explaind

to

on

the

On

+ MeV)

+ C

+ d

the

of

yb mechanis. of

in t a e

heating emison

rates

the

A sati f c ory

Synchrot .

the

a carbon

at ributed t o the oalescn in t h e orwadf direct on, the contra y, the distr bution of t h e opti n t o celrat

y(380 n

also

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the coalesn

prot n

deut rons

a ascde a residual nucleos

and

are explosiv

light

from oxygen

y(580 X

of

of

contribu on

nevig

break-up

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+ MeV)

neutron Fermi

Since

and

sub eq nt

in

emison

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Fig. main

+

part

dominates

break-up

at

d

Later

fragments.

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of nucles.

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elihw

of

RHIC,

si

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X

1.0

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part

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part

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produce

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undergo s

of

compar ble.

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the

with

nucles

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0. 5

a" W c"

150

the

the in t al a oupled-c t o a pure with the L = 3 , i.e inces it si os

03

some 3He(y’,p )n

be

than

important.

an lyzi g

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upto

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is underway.

ben

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a functio

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posible of

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Mainz

[10, ].

cal u tion

leading

state the

the

al

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also

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and

figures, the

the

monticaly transit on. to

the

transit on

verticaly nucleos

fo

[10, 1].

used

(In

and the

that are is expctd

is

the

has rewop

1M

the

rof

proces

ev nts

decras

takes

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pres nt d.

MeV/c

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05

(MeV)

compared

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El

Figure whic

theory

l iw an lyzi g

kcal

p-sytem

and the

, the si lowed.a section

section

the

(’So),

In

data, E3

cros

state

the also

the cal u tion

E2,

t o det rmine 2N(pp) 3He(q,p )n result The 320 MeV. Pm 5 wher 3He(y’, One polarized Pm region. no asym etry

2N(p )

anti-sym etriza on

of

TAGX El, smal .)

The

. I

04

03

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. I

I & . /

01

rof

ther fo

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for region

rewol

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165

t 0

Figure P, tal y

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> 150

The

MeV/c.

polarized

Pn l

prot n

I 051 .

.

40

MeV/c .

distr bution

open

~

120

. v

cirles

~

160

l

0

are

MeV

= 240

Ey 1

.

08

angular and Solid

phot ns.

.

of

for

.

the

3He(y’,p )n

the

.

~

08

evnts

.

120

due

l

.

evnts

to

MeV

= 082

YE

l

40

~

l

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= 320

Ey

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160

5 051

and

and

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VeM

5.0

F 1 O 5.0-1

Figure MeV/c. 0.2(

12.

The

solid)

Figure

rof plot ed enrgis tA sy tema ic l

0

Prelim nary ,0.5

12

In

thes this

7E =

toge h r mo ent,

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curves

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240,

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160

data

0

result

labe d

of

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the

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120

SO

40

0

061

80

40

Q,(?

prelim na y

280

fit ng,

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are

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figures,

08 40

and

relativ

lines. si

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VeM 320

The stil

are

prelim na y won

of

ratio

in

in

strength E1/E2

y

the Fig.

carefuly

the

31

ratio

’+ with

the

being

of

transit on

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oo(

of

120

160

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strength

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the

can

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and

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varied drawn.

group

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16

TAGX -P.Wlhem

40

YE 13.

The

El/E2

prelim na y

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03

20

Figure

et

ratio

(MeV)

compared

with

08

;5

^n 5.

* (yd->pn)

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Kolb A

42.1

et .la

Bena

I \\

06

et al.

3

lo2

1

ani rkULebdv

+

0 03

02 10

YE Figure The geth r. cros

14.

data

In

for

The

section w h

Comparison

Ther

E-,

A

20

0

some

0.6

b

’01

.3

*

a(yd->pn)

I \

04 5

W

1111.

a theory

data

Fig.

of

them

are

The

rewol solid

sevral [12, 3].

14,

the

E-, a scaling

are

swoh

factor

with data

det rmined The

2N(pn)

YE cros

set deut ron

the

rewol the cros

1.24 si also plot ed. The sim lar ty that of t h e deut ron cros ections si rema k bl . eW can conlude in He3 cales to that of t h e deut ron Figure 15. hows 4He(y,pn)d scaled deut ron phot dis n egrat o si our surp is ng t o find that ther 041 MeV, hicw si n o t bservdo

section.

plot ed

fo

deut ron

2N(pn)

toof

1.24

,.E 3He

data and

section phot dis n egrat o that cros

Figure The geth r. cros

revo

4He cros

of

for

cros

the the phot dis n egrat o section

si a igb ni t h e He3

3He

such

E-,

section

phot n

case.

rof

The section

The

rewol solid

with

phot dis n egrat o

section.

E-, line

yb

TAGX

dep n c

cros

a ediw

,.E

absorpti n

To

with

section range

7E

rewol confirm

a factor ro j u m p

revo

is

plot ed

a scaling

of

the cros

data

from

section

thres old

cros

are show

a scaling

section.

plot ed

the factor

E-, toge h r

with 2N(pn)

40

(MeV)

4He(y,pn)d

a t rewol

with discrepany

data

15.

03 20

01

(MeV)

3He(y,pn)p line

0 40

deut ron

6.0 of

region,

and with

cros of

to-

the

to

a idew -,E range. .18 -41[ In t h e figure, of 6.0 si plot ed toge h r. in magnitude around t h e absolute magnitude

section

rewol

50

factor

of

VeM

np- air

the fo

,.E

the

to

It =

I

761

cros

the section Hom a 07

section

neutron MeV/c

p)

(7,

that

mo entum

obtained

the

cros

e t al.

TAGX,

we in

]91[ was

section

absolute

yb

are asigned

this

plot ed

of

magnitude

deuc vector

.yaw

of In

due

TAGX

with of

the

the

toge h r. to

the

the the

5.1

2N(pn)

same that

inclusve

2N(pn) TAGX

The

4He(y,

ev nts. figure,

the

bump

of

Hom a’s

proces.

cros

16.

section revo

4.

140

the Ther fo

for

The

4He(y,p)X

4He(y,

neutron

VeM

double

l a

p)nd

mo entu

si s t r o n g l y

the

dif er ntial

result

measur nt

at section

16

cros

in

Go d

around

agremnt

si cor e t.

60

05

04

yb

det rmin

cros Homa

desir

of

to

section

the

2N(pn)

the

understand

the

section

Hom a’s

07

integra ing

of

MeV/c

4He(y,p)

cros

measur d

data

at

the region

revo

de uc

by

around confirm

I

09 80

07

(MeV/c)

e t al.

from

vector.

yb

swoh

= 30"

8p

Pp Figure

Figure

section

h....,.,..,....,....,....,....~

30

inclusve

observd

4He(y,p)X

p ) cros

TAGX

[19].

Solid

cros

what

for

4He(y,p). 4He(y,

is goin

cirles

pn)d

section

covering

on

Open

wohs

at

cirles

the

cros

section

the phot n

this

wohs diferntal

integra d

phot n

the cros

enrgy enrgy.

of

CON LUSIONS

In t h i s and 4He neutron measurem nts absorption absorption cros section A icrospm Phot n extracted. n p cros a realist c

fo

pa er,

measur d

ew TAGX yb

absorpti n section,

evaw

proces saw The

enabl d a kinemat c l y in

the found

cal u tion cros functio

pres nt

with

np- air

the

yb

two

section

suced two

to

have suced

the

result to

nucleos

saw

to yb

and

su

TAGX

det rmin

be prot ns

saw difernt

revoc

complet

in

quite

simlar found to

the

fo

spectromet r.

to

the

a ediw .yaw

rep oduc in rep oduc

E-,

to

This nucles.

rof 3He

phot dis n egrat o

3He

to

dep n c .

be

saw

Large

kinemat c l

saw and

that about

ac ept n

the also

of two

the

magnitude

observd

range, esntial

The cros

4He,

to al

and deut ron

the

A

exp rim nts rof

orde microsp

cros

section

the and

to

E-, revo

phot dis ntegra ion.

identfy section

the

to

cros

cros

perfom

the rof

a wide cal u tion

for

prot n

dep n c

the

smaler of

and

both

section

than section,

3He phot n phot n

E-, that

and

the

of

of

range.

the

using

saw

the but

168

by

failed and

two

to

prot ns

the

ac ount

saw

prelim nary

rof

E.,

the

measur d result

dep n c .

to

are

study

pres nt d.

The

the

an lyzi g

phot n

power

absorpti n

rof

the

yb

phot n two

absorpti n

prot ns

in

detail,

REF NCES .1

2. 3. 4.

5.

6. 7. 8. 9.

10. .1 12. 13. 14. 15. 16. 17. .81 19.

H.Arenhov1 Sup l.3 Maruyam M.Kobay shi M.Vanderh g E.Jans T.Emura S.Endo, T.Emuar T.Emura K.Maruyam K.Nik , .P .P .P B.L V.N A.N .uY F.Balestra F.Balestra S.M S.

(Springe -V la ,

Wilhe m, Wilhe m, Wilhe m,

.M

Hom a

and

.M

e t al. and

e t a l . , ucl.N e t a l . (TAGX Ph.D. thesi , e t a l . (TAGX e t a l . (TAGX et Ph.D. thesi , J.A J.A J.A Berman S.C Fetisov, A.N Gorbun v, Arkatov et al., e t al., Doran et a l e t al.,

(TAGX

Sanzo e, K. ond ,

e t al., Phys.

Nucl. Journ.

al.

(TAGX Niskane Niskane

Col ab.)

Gorbun v

Nucl.

Phys.

A475

Col ab.):Phys. Col ab.)

Col ab r tion)

Journ.

and

and and and

A59

.786

Hiroshma

Sci.

H.

H. and

Phys. Nucl. A59(13)47.

38(197)45.

(195)

Hiroshma

Let .

Rev.

Methods

Methods,

Rev.

Rev.

Phys.

Univ.

C 94 Let .

Univ.

Phys. Phys. Phys.

Arenhovl, Yergin,

Arenhovl, A.

49(17)5.

Phys.

(1987)

lO(196)

T.

Phys. Varfolmev,

1623.

1(970)63.

37

862

A57,

Rev.

673A

(194) 47

A5,

weF

A376(

.912

: Phys.

Arenhovl,

H. P.F

Instrum.

: Phys.

:

J . ucl.N e t a l . , Sov. J. Nuov. Cim. Nuov. Cim. Nucl. Phys. Phys. Rev. 36C Sov.

(1987)

De u t e r o n ,

fo

Nucl. Instrum.

Sci.

Niskane Fultz

Photodisintegration 19)

Wien, Col ab.):

(195)

Let . Let . Rev. Rev. C10

19.

Nucl.

(19 6)

System

196)35.

35.

R597. 193.

(194)

Body

.40 1035.

B39(17)25. 53 B Let . C51 (1974)

(19 5) Phys.

47

(19 4) 21.

(19 5) 71

109. .1482 (1965)

1034. .503

Hadron

K.

and

02

Maruym

Nuclear and

Elsevir

Physic

.H Scien

htiw

onukO B.V

Phot nuclear thre -nucleon

cros

G. 05 83-1

W.

Orlandi ,

Departmen

fo Pov

bRus ian Kurchatov

Res arch

role

ap lic t on

After

a brief played

yb

are giant

an lyzed

1.

INTRODUCTION

have

knowledg

dipole

One tromagnetic t o understand sizable mechanis .

of efcts reach d

of

In

fo

in

thre-nuclo

to al

weiv

of

whic ad res ing

other can

the nuclear a eryv conti u m

stil t o d o for kinds of ap roximat ons I t si certainly problematic body orcef from spurio sta ist cal (numerical). In orde t o cirumvent ago the LITM saw pro sed, using bound state techniqu s

hig

Efrosb

OW0

and

Rusia

the

secrof

isue si t h e be

observal,

the

in role

Lorentz

Universty

si discue.

of

the

of

misng

exp rim ntal

study thre-body besid

the

isue,

obstacle a method [l].

howevr,

uniqely

integral

H3

of

The

of

and

result

wef the

body

transfo m 3He

rep s nt d In

fo

sy tem force.

bind g

the

whic

gniwol f

swol a

yb a sketch

to

the

cal u te

Sask tchew n,

si pres nt d.

enrgis

t o it a n d learn a gib ifcultyd sy tem ni their inalf sta es. While degr of acury in t h e treatment sta es. Thes sta es are very ifcultd one si fteno forced t o introduce can t o disenta gl the presumably not fects introduce y b any ap roximat on, this

ascribed

the

role

kaisumoT

Physic,

about

the

Institute ,

Engier

clarifyng

E.L

and

Trento,

,wocs M

phot dis n egrat o

important whic

Kurchatov and

sy tems

of

1238

,1

S7N

introduction

thre -nucleon

Universty

Italy

Physic

the

interac ion

961

V.D.

Physic ,

(nento)

to

the

resvd.

Leid man ,

fo

resona c .

sthgir

lA

forces

Centr

Can da

Probes

sections

Square,

Departmen Sask to n,


method rof

the

strength

In

In

thre -body

yb

particular

of

(LITM)

particular

puzle

sy tem the in

means one

3H

fo

dluow

and

the

its

4He

the

-cel

3He,

wohs

ekil

more about i t s orign and s i rep s nt d yb t h e scare the wef body techniqu s of bound sta es, uchm si t o treat exactly, and the mask the fects f o inter s . large efcts f o the thre be i t s y t e m a i c or

conti u m of

the

inclusve LITM

sta es l iw

cros

a wef be

given.

section

years

170

THE

2.

LORENTZ

The

wher

of final

inclusve

the

the

ar ives transform

With

si

\T.lf

fo

the

@(OR,

R(w)

yb

R(w)

help

of

Eo

equation

vanishe

(H The bound Eqs.

method (2)and The

3,

in

with

orde

This Sieg rt’s to this

second

at

large

dt(H

step

R(w)

-

to al

state

i0r)lG)

char te iz s the

form ap roximat on

unretarde

theor m.

fo

ext rnal

directly,

since

cal u tes in

inclusve

the

an case

integral

has

proces

this

imples of

cros

under

set

Thes

section.

of

form

considerat , final

respon

the

transform

a Lorentz

the

sta e

The knowledg

main

fo

kernl

evaw

functio s

it

and

the

idea of

then

integral

the

that

- iaI)-’(H

OR

&J -

-

f

OR

)OS[

iOI)-’d

distance

si t h e

H,

Hamilton

fo

two

k\

ekil roF

Details

step .

si t h e exist a bound

of

the

cros dipole

operato dipole

I t si know adequate

G

and

si d e t r m i n e d

yb

the

(4)

ni

inverso

R(w).

> 0.

the

dpo). That

norm

of

esntial of

this

First and the

pur ose inverso

thus,

state

Eq.

adv nt ge

contra y

evaw

transfo m

functio .

alre dy operato

section

operato

that rof

invest ga

are

as

are

far smal

as in

enrgis

the

discue

LITM.

This

In

cal u ted a set

rof

fo

can evaw

done

using becaus

functio s, as

positve in

be

fact,

the

norm OR

Ref.[2]

of of

values

SECTION

rof

includes

OI),

@(OR,

si cal u ted

procedu

si olved.s of t h e t o conti u m

(4)

CROS

the

probe

the a ompletc enrgy.

and

excita on

one

enrgy

=

phot absorpti n unreta d

the

an

(3)

the obtain

functio

wohs

OE -

whic

particular

can

to

PHOT DIS NTEGRATION

using

the

one

METHOD

a sy tem

el ctromagne ic

In

yb

proceds

10

THE The

then techniqu s. (3)

to

given

evaw

denot s any

Instead,

closure

+

state

inverso.

ground

0R

a dexif

3.

yb

-

si

w

of

cal u ting

($I$),

si t h e

Eo -

functio s.

state

while

avoid

IOQ( =

01)

=

wher

ingred ts

of

operato

ground

si t o

evaw

at

functio

a transit on are the respctivly,

es ntial

LITM

state

TRANSFORM

respon

0

and

90

functions, are

INTEGRAL

the the

woleb

to al the

efcts enrgy efcts

cros

pion

of range

thres old

exchang section fo

N

studie

si conerd and

s i computed

cur ents

N

her . forces

eW

due cor e ti ns consider

to

the

to

the

@

17

proces. respon

The

functio

phot absorption

cros

R yb

47r2(e2/hc)~, =

? C

to al

section

si

then

nevig

in

terms

of

the

dipole

)6(

R(w~)

wher

R(w) sA one

This method The method" and (UrbVI )

05

shown

has

eW

the

pres nt

as

r-space

and

section

gniwol f

20

the

the

[5]

VeM

with n Lorentz in

result

Ref.

Tucson-Melbr

pres nti g

In

13

our sets

and thre -body theor tical result and Phil ps [9], ation a s :swol f e h t noitargetnis dot hp eht raelcun noitcare studies of t h e d o ton tah yeht tions, eht rosnet snot rp in He. particular the t o include the In Figs. 1 and and tail regions. only the N force are quite also indep nde t the result .

exp rim ntal of

break howevr,

obtained poten ial

esu

a large rof

H3 (TM)

As

equation

the

LITM

Hypershical

number

transfo m

[4].

of

of

has

and

N

3He

R(w)

cal u te

Harmonic

points

OR

ben

done

using

poten ials

N [6]

to

using

the

Argone

ew

models.

imples

(CH ) betwn

41VA include

expansio

0 and "Regulariz t on

the

that

051

MeV.

[3]

poten ial Urban -VI

the

DISCU ION

situation particular

integral [2].

Cor elat d

rof

(7)

W)

the Schrodinge-lk

the

and

AND

Befor

MeV.

=

of

describ

Bon -

previous

the

done 01

RESULT

About

the

be n

rof

inverso

in solve

Eo

-

I ( q ~ z l ~ o ) 1 2 ~ ( ~ f

to

has

4.

theor tical tems.

fd/. =

er w

on

the in

up

result

198 the

a wef

phot dis n egrat o

cros

laciteroeht

the

data section conlusi

Berman,

should exist

from of

cal u tions

H3

be cros

rey M

the and of

3He.

section

Gibson

and

said

about

period tA

of

the

1964-8 Olson and Ref.[7]

that

]7[ Lehman

time

the

er w

exp rim ntal thre-nuclo rof the

sycomparing

]8[

enrgis most

below and

ac ur te Barbou the

and

-owt

the authors of er w judgin sitube d e d e n erofeb e h t latnemirepx stluser rof fo ydob-e rht ielcun nac tse y l e v i t a n a u q eht e g r a h c yrtem s fo [This saw the main isue at that time, hicw led t o compar tive two mir o nuclei]. ehT tnes rp laciteroeht sledom are l its yratnemidu in edulcni ylsuoenatlumis a tne si noc tnem a rt f o e h t lanif eta s -caretni ecrof in e h t telpirt ,noitcare and eht bmoluoC noisluper ne wteb eht In t h e result ew are gnio t o wohs al those drawb cks are cured. In LITM and the esu of t h e HC ap ro ch t o evlos Eq. (8) have dewol a su ful final state interac o and the Coulmb efcts. 2 e w wohs the to al phot dis n egrat o cros section of 3 H in t h e peak 1 One notices a izables tcef due t o the thre-body interac ion. I n Fig. orcef Urban VI result a r e shown. The efcts of t h e Tucson-Melbr sim lar. The gnirewol of t h e peak due t o the thre-nuclo interac o si NN poten ial. The esu of t h e Bon poten ial does not hangec on t h e

eroM

in

Fadev

Faul,

words

krow

l aw

271

0.0 0

’

01

20

.1

Figure

A

becaus

Total

quenchi g

fo

phot dis n egrat o

the

( T;(~H) wher

cros the

peak

) si t h e

triton

gniwol f

of

due

reason.

roF

to

charge

of

NN

3H

50

06

[MeV]

section

the

04

03

ro

so

the

interac o

3H in

caled

the

peak

region.

could

Brems t ahlung

in

princle

sum

rule

r

0.25

exp ct d si alidv

radius.

n

03.

be

1

0.2

-

E

0.15

d

01. 0.5

0 .0

Figure

for

presumably to

Total

2.

Since

its the

sum

’

NN

rule,

reflct

cros interac ion

in due

size. in

to

a rewol

10 [MeV]

08

phot dis n egrat o

the

shrink g

06

sevig Becaus the

invers

pek.

fo

the In

section

ad it onal enrgy

ro

fact

validty

bind g this weight.

fo the si t h e

of

120

3H

region

in

sum

to

140

the the

rule

tail

whic

sy tem

a smaler

region.

sevig

it is lsoa charge more

responibl contribu on

radius

l iw

173

Besid section

obtained poten ial ne t, combinat Thre separ t ly. can is. to force below to becaus efcts in break ne d .

lowering whic

The

MT

but body

The

notice

Only

in

be

pion

the an

inclusve

Ref.[10]

fo

forces

respon ibl "bind g

up

separ t ly.

phot reactions.

imples

invest ga on

compared amplify that

N

the This Malfiet-Tjon

also

range

break

reaction

reactions.

si purely

Eq.(8)

"tcef

sug e t

the

are core

ther thres old.

Sucesfl

for

furthe

fo

that

it in

peak

soft

short

fo

This thre -body

the

enha c d.

Ref.[12]

poten ial a eryv

soluti n an lyzed

si

is

shown.

interac o

tcef

central,

and

tensor

is

obtained up

In

is eryv lit e for a izables This tcef discue the posiblty Considerg one can In t h i s resp ct

the

si

contra y t o .41VA cor elations

this

rof

contribu s

particular reactions

poten ial

above

enha c m t sem of

efct.

the in

hope in

this

an

to

ext nsio

the

be

the

find

Fig.

(MT) the enha c

direct on

have

of

this

the

interac ion, cros

the

cros

oy(uy)

roF

comparis n,

and that

chanels

whic

LITM

the

in

cros

chan els

tcef

result large started

to

pion

section

T=1/2 to

elihw section

in exclusiv

exclusiv

of

the

for has

for

section.

efcts

tail

Ref.[2]

cros

rather alre dy

on

woleb

This investgao

large

tcef

say

thre-body region.

an

owt

N

the

of

alre dy

nev

TRSB

wohs

to

.2

[l ],

isopn

the

3 we

also

can

a pure

peak an

ni

one

of

on

exp rim ntal

that

owt Fig.

to in

an

to

So

contribute

dep n c

has shown

a tensor

the

cros TRSB

comp-

and

a T=3/2 section

chan el si i n t e r s i n g t h e thre -body in t h e egionr with no relation si very inter s g f o thre -body orcef sen it v y si found thre-body reactions [13,4]. It

T=3/2

cros

result

the

thres old considerably.

the

the

si

570.0 560. i5 I

E

Y

0. 5

6540.0 0.035

3.

Figure

comparis n precis force

In

eW

Fig.

Total

08 90

100

phot dis n egrat o

4 the result rof 3He si g o d , ven if t h e data are ne d , espcialy whic are of t h e same magnitude ouldw ekil t o iscud her

110

cros

briefly

are uncertai s

section

ym

pres nt d if

one the

as

120 [MeV]

those

wants case

in

of and

of

the in

130

H3 compared to 4He.

Fig.1

in

140

the

T=3/2

chan el.

to

exp rim ntal det c

exp rim ntal

the In

Ref.

efcts ]61[

result

are the of

the

theor tical

large.

data. More

thre -body result

The

471

, -

0.2

-

3He 1.6 -

2.1 -

Y

-0-

1

0.8

4.0

V14+UI i

0.

obtained with the LITM and exp rimental data. From the realist c forces enha c s the the peak region. Ther , on sem t o be sizable and relat d, on t h e bind g enrgy. Such contributes with 4 VeM to the 4He si n o t only con e t d to t o t h e mean square prot nnot ap ly a s simply. evrthlsN the thre -body force ni t h e resonac it requi s a somewhat Thoug sy tems the LITM can be ap lied other hand one has t o remb thre and fourbreak up chanel body sy tems phot reac i ns realm f o invest ga on of t h e This del Universit

Acknowledgem nts

krow

has

ben

partly

e del a

Ricera

sup orted

semiraltc the

cros

study via

efcts

bind g

the

section

contra y,

charge

pro e ti s

woleb

central thre-body

the are

for

modern pion

the charge

in

realist c

the

[17]. of

computa ional

also

thres old of Isti uto and

extr m

the

the

oS 4He

OTAN

phot dis n egrat o

trof e

So

Nazionle

argument

si

desirabl

also

an

the

largey have

very

tcef the

to

has the

thre-body

the

4He.

interac o s

ac urate misng.

in but

ew

but

radius,

,rev woH

of

ielcun

tail, quenchig

large radius,

yb Scientfa

interac o s

be region

are

nev enrgy.

distance i t dluow

large that

of

ad it onal

efcts

Ther Brems trahlung

lit e of

of

to

exp rim ntal

than

an

exp rim ntal in

forces.

grant

di

Fisca

nucles.

efcts

cros

rof rof to

the

efort

in

open

V. D. Efros, V.D. Efros,

W.

W.

Leid man ,

Leidman

and and

G.

G.

Orlandi , Orlandi , Few-Body

Phys.

Let .

Syst.

B

38

26,

(19)

,-owt

a wen

Min ster0

(194)

in does

role

.031

.152

of

has

force

On

both

in force

section.

thre-body

REF NCES .1 2.

found

rule

Nuclear,

.405179

the

esu

sum

pro tional

orde

N.

is

term

data

the

ecrof-N

thre -body

bind g

invest ga

thre -body

the

it does this in

that

tcef

the the

inter s also

over stima d

learnt

fo

few

the

571

3. 4.

5. 6. 7.

8. 9. 10 1 12 13 14 15 16. 17.

R.B R. R.B S.A McKel ar, C23, D. B.F. I.M (1970) V.D. R.A R. C6te, 269. V.D. A. man , V. V.D. Se

Wir nga,

Machleidt,

Adv.

Wir nga, Co n,

M.D. Nucl.

(198 ) D. Faul, Gibson Barbour

165.

Efros, Malfiet

De Tour eil, R. Lapian ,

N. e.g

Sov.

Efros,

Fetisov,

Leid man

and

in

prepar tion. G.

Orlandi

W.

Smith,

Phys.

Rev.

Scadron,

Lehman,

J . Tjon, B. R o u b e n

A.

Leid man ,

N.

C43,

B.

T.L 19. (19 )

P.C P.

rey M

Phys.

Rouben

and

M.

24

and Phys.

and

Rev.

G.

L. 94

41,

Train ,

and Orlandi ,

T. Rep.

; S.A

Co n

D. Olson, C1 ,

(1975)

Let . Phys.

A127,

Sprung, D. W . (1985)

A.

Rev.

B.R

com unicat on). Rev.

Phys. 189.

158.

McName,

Orlandi , Phys. D. W . and

Univers ta

Gorbun v

Ainsworth, (198)

G.

Phys.

and

(private

(197)

Phil ps Nucl.

J . ucl.N di Laure , Tesi

and

A317, Co n

S.A Berman, D. R . A.C

and

De Tour eil,

Efros:

Phys.

L.

and

W.

Nucl. Phys.

1790;

B.

R.A

di

.L

Sprung,

Trento, Varfolmev,

Phys. Prog.

Bar et , Phys.

29; (1967)

19,

Nucl.

Rev.

Phys.

138;

A24 ,

Nucl.

(19)

78,

Phys.

Rev.

C1,

.1

(1975)

Phys.

564

A273,

W.

and 5104

Rev.

849. 47.

Phys.

Lapi n

Nucl. 54

(198) (1976)

B.H.J.

and Phys.

(197)

A. Let .

C24,

C13,

1207.

Blat Glocke,

B408,

16 .

19;

Rev. Phys.

D. W . E W.

and

Let . (196)

(1984)

C29,

257.

A71,

(19 7).

(1965)

; J.

(1976)

Leid305.

ThisPageIntolyLfBk


Hadron

K.

’

dna Maruym

02

Nuclear and

Elsevir

Physic

H. Scien

with Okuno

B.V

Quasi-deut ron Y.

Hirenzak ,

Physic

yb

eW

have with

model

of

dis ntegration caled Levingr

resvd.

Ume ot

absorpti n

devlop

3He

a henomlgicap 3He

pn

yb

rev woH

and

K.

pairs

ther

phot dis ntegra ion

Universty, and

data

4He

Kume

Women’s

of

exp rimental

.l ew

71

and Nar

reactions

data.

er w

stil

4He

obtained

at

interm diate

selctivy

remain

630-85,

Nar quasi-de t ron yb

the observd.

certain

model

phot n TAGX

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group

in

The

discrepan

to enrgis whic

data

describ

and contribu ons be

can

betwn

phot dis n-

compared rep oduc

cal u ted

the

from

rea-

result

INTRODUCTION Phot dis ntegration the

few-nuclo

remain inter sted

sthgir

rof

De p a r t m e n t ,

1.

theor ical y exp ct d

lA

Probes

picture

S.

tegration result phot n sonably and


to wel-kno

be

yb the

Levingr

in

phot dis ntegra ion Levingr pair

pn

rms radius of p n pair. tum transfer data qualit vely phot nuclear Since be n obtained of 3 H e ( y , evnts into method absorption thes contribu ons data are

and

lactor

[3].

values reactions.

1987, pn)p

[8].

-owt yb

complet y

and eW

section

enabl s

ac ur y

pn

yb

the are

and pairs

later

whic

the

saw

thes

and

updated

trinucleo

exp rimental

Experim ntal

in

are exclusiv

nuclei of

the

selctivy

number

and

to

the

model

obtain

sy tem

whic

reliaby.

saw

studie

using

those esntialy

fo

[4].

phot n rof

the

[5].

They first

absorption

do

evah

time

the observd.

da.t , not

picture.

of

deut ron

rof

studie since belivd

and

twoefcs,

in

the rega din

this

obtained

yb

the Another

any

using

be

contribu ons extra

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posible

inter s g

a long

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relativ pair

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mo entu precisly

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os

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moen-

nuclei

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ekil

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in

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phot -

of

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si

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wavefunctio

range the

stil

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factor, wavefunctio Recntly,

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ther

both naively

induce

quasi-de t ron

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are structure result .

exprsd

the

time

are

the

a np

reactions kinemat c l y have

for reactions reactions that

using

using rof

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proces

exp cta ion,

They

target

ielcun

the theor tical

with

result

absorpti n

[6,7].

of

thes

[2].

invest ga d

since I t houlds include

is

data

many Thes

phot dis n egrat o

it

Despite

rof also

works,

rof

theor ical y Miyazm

deut rons informat

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saw

data rof

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det rmin

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Futami

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very

of

us of

TAGX

4He(y,pn)d

cal u ted betwn

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factor, This

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el ctromagne ic

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reactions

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rep oduc

sy tem

certain The

and

pions

is

cal u te

that

whole

have data

phot n in

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178

final

sta e.

it can To [9,10]. in t al

this

A

data 20 be for denc

whic

result theor tical enrgy ef cts, 4He(y, todis ntegraion data

compared The

section

MeV).

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this for

both

can

in

detail.

the

final ew

150

theor ical y.

reactions

reactions

compared

data observal

[l ]

Their

be

the data

cal u tions

pa er

section

=

at empt

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importan

both nucles,

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7E Tezuka

pn)dse,tar

cros with

dep n t

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it extrmly

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3He(y,pn)p

in

They Since

4He(y,pn)d around yb

think

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to al

angular

we

pairs

for

In

reaction

triplet deviate

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rof

directly, ]7[

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state

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with n

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the

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compared

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same

data

cros

exist

has

roF

studie

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ther

[lo]. that

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diferntal

directly.

not

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ben

deut ron

section from

This

consi te

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(i.e include

cros

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to al the

theor ical y

chan el)

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this

spin

observal

section

and

result

singlet

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section investgad

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has

not

t o know yb configurat s

nucleoi, at

rewol

Wilhem

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a ormf data

enrgis

et mesic,

found and

a strong

theor ical y.

whet r

enrgy

data rof igher nergis, but t o the data revo t h e entir inc de t at enuation factor t o acount for specifd as a deut ron. the reactions 3He(y,pn) s ecta or pur ose e w investga both 3He theor ical framewok and try t o eW cal u te al observal ni Our theor ical studies are repo t d

and

that

(Ey

that

theory

the

suitable

5

could

and

are

phot n

distor i n and

the

dep n-

Theor tical

ther

al.

rof

no

4He

rep oduc

phoin

al

forms Ref.

FORMALIS In

this rota Wps )np observal

In

(l),

ind cates exp rimental

yb

b, c ) =

our

model,

expr s

phase

as

in

each

we in

A

final-sta e, In

section

thre -body

writ en

A(a, and

They

region.

2.

wher the vari ble for

understo d

pn

cur ents.

[12]

3He(y, al state be

be

the A(.

in t al

describ

and

suitable

target

y

. . ) si t h e

the

in t al

+

a2 the

+

b2 ew

phot n

square

consider

c2

Kalen

result.

and/or

+

-

pn)dspecta or forms

space

the psectaor

4He(y,

nucles,

flux,

only

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3He eW

integrate

amplitude

directly

as

with section

and/or

The

quanti y

Since

rof

ew

the

the

and B s cor esp nd

4He, the

model

final-st e

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to

whic

si

dluow

data,

A(y,pn)B

ew

ekil

evalu t

si t h e

specta or

phase

space

pro e ly

ap lied

to

cal u te the

reaction

to

the

ap ro iately

to

both final-

can

particle

Mandelst m

normalize

in

the

cros

2ac. -

the

cros

hci w defin

- cb2 the

reactions.

compare

dspWta or.

A sy tem. functio ,

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exactly.

ba2 of

our

deut ron of

(2)

the

chan el

phot n

rof

absorpti n

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in t al

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in nucleo

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971

using

the

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al phenomlgica

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In

picture

I wher

in

of

the

orde

Her

pf

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cal u te

describ

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rep s nt si roughly ew

our model are directly for both entire en rgy phot dis ntegration spectro i target .eH Both t o change the consta factor cros section pn the inglets shown t o b e ap roxim tely section. This evig a minor should lsoa mentio from the begin ,

In

the

square

121

are

(g)

the region

observal

factors overal when

into pair

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.VeM

eH

y absorpti n

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target

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eW cros

the nucles

esu

section

quasi-de t ron

a

as

12: pn)

particle

l2

phot n.

using

B in t h e

mo entu

to

be

146

s i evalu t d ekil t o describ e w can cal u te He3 and 4He target of inters using reactions. ,rev woH nor the fects efcts are exp ct d normaliz t n each reaction it si necsary. in t h e in t al 50 pb decras t o the her that the since e w evah

region

rof

the

PB

that

p)n

[13],

04 -02

+(PB)pn-B

the

Fermi

evalu t d

=

of

d(y, of

data

7E

t-

the

NUMERICAL

3.

the group

T(ypn absor

estima ed

radi . would

of

1

that

specta or

varibles

~ n )

+ -

(g) section

the

evalu t the

tif enrgy

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B

wide

to

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ew nucleo

pair form,

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TA

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II,

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pair

205

can

neith r to

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model. cal u te

the

rof be

take

specta or

4He

for betwn

from adv nt ges

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incdet

phot n

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of

pn

to the the

value

enrgy

two

the

particle

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observal

tcef

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The

compared rega din

the

functio

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and

VeM

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t varibles

functio

the rosc section . e w are fre to a par met r t o normalize the absolute In t h e odelm e w d o not include contribu ons state, hci w er w evalu t d in efs.R 9][ a n d a t 7 E = 01 VeM for t h e 3He(y,pn) s ecta or monticaly a s a functio of 7 E a n d phot dis n egrat o reactions a t igher enrgis. final state interac o s i partly include in data of t h e deut ron case. used the tif t o the as

of

case

Mandelst m si the

data

the

in

introduce

to al

from cros

is know the

model

the the

and of

[lo]

of

data in

deut ron deut ron

pair

pn

a

the and to

eW

RESULT 3He(y,

this

section .18-6[

pn) specta or

ew Other

compare numerical

reaction

our result

and

cal u ted

the

are

4He(y, found

to al

cros pn)dspecta or in ef.R

section [12].

reaction

with

exp rim ntal

taken

yb

the

data TAGX

rof

180

phot n experimental data matical [14]. target. se m MeV.

eW

show over

pair large

be results tribution mon t ical y pos e are deuteron

As

to This

total

ew

be in

dif er nc

the for

wil the

cros

observ d can

due

is cor e t d results to

se

in tial lower

be

at

consi tent

total

the

region

Theoretical

np

the

absorption

125 =

with

op osite

the

to 205

phot n those

en rgy, dep n ce

cal u ted

are

by

the 1 as obtained

region.

extrapolation

the

figure,

be whic

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deviate

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include

the

A excita ion,

could sta e:

fo

Fig.

for

only

from

in

sections

kinematic l

-

with

chan el.

sections

phot n

caused

7E

cros

proces

while

explained

was more

MeV.

In

Howevr, this while

3He

by

evalu ted greatly by

20

en rgies =

dat pf

by

.1

ref. Total

Total

en rgy.

[6]. cros

150 over

taken changi

MeV.

cros The

by

a wide

the by

sections This the

dif er nt

fo

TAGX range

section solid

en rgy wavefunctio

to

fo

curve

group groups

the dep n ce investiga e

the

4He(y, ]7[

and .18 -51[ fo

3He(~,pn)pspectator

indicates

pn)ds ecta or

found

the

region,

a1

the singlet

[9,10]

result

body

the

25

may contribution. the

for

pn

the

becom

section

MeV,

this

fo

pair)

np( en rgy.

cros

unobserv d absorption

including

experimental

I

two

phot n

the in tial at 7E = predict siglet configuration e t a1 [9,10]

the by

dif er nt al

from

fo

dep n ce

data

et

30

peak results

fo

Wilhe m

the

the

two-nucle

the

en rgy the

by

inc de t

the

chan el

the

I

vE

Figure phot n from

integrating contribution

by

theor tical

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fo

show

cal u ted

inclus o from

Wilhe m

100

using

deuteron data the

en rgy the

I

0

by

The

the

by

phot dis ntegration

a functio

pair peak

and

the

theoretical

singlet

values

flat

in tial

pn

a function MeV.

Da t a

model in at fo

shown

kinethe

whic 275

the

to

con-

increas Our

The

or

pair

results

ev n in

the

I

400

(MeV)

the

to

is almost eW hows the pos ib l ty 4He. eW also

have

result

with

reaction

a strong like a ’disconti u y’ t h e cal u ted f o rep oducing multip ed

reaction

as

wer

pf=150

measur d

en rgy

dep ndence result

the

cal u ted

the

at to

in

en rgy

fo

sev ral the Fig.2

lower cros

are

inc de t

phot n

around with dep n ce

taken

en rgy sections

7E varing

18

yb exp rimental

a factor

to

rep oduc

en rgy

h

v

A

the

dep n c .

14

9 .5

0

peak.

eW

I t si difcult

dnif

that rep oduc

to

our

result

the

do observd

not

’discont u y’.

rep oduc

the

20

Figure 2. T o t a l phot n nergy. 20 VeM solid( spectivly. calculated in t h e A en rgy = 02 eV,M 1.67 [7] (solid cir les),

eW

4He ad it on the

eW

-

subtracting 7E the

3He(y,

cal u ted deut ron information

region.

to

for

estimate

40

]51[

data

at

whic

the

2-body

The

(squares),

4He

due

absolute

normaliz t n

to

normalized

MeV,

two-bdy

decay

(dot ed

to

factors

1.8

(cros e ),

the

fo

than

krow cros decay from our

include

cros large

largest

40

are

pf

]71[

reaction

with

and

rep oduc

rof

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value

may

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curve),

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contribut on large

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section

phot dis n egrat o the

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her cros

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03

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mentio

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MeV,

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ind cate

30

result

to

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section lines

curve),

like

contribut ons can older

cros

(open by

in chan els, the

cir les), Efros

the

result

er o s.

rof

the

et

to al.

It

MeV,

are

and

]81[

1191 in have

r~)~He case s i ap roxim tely 05 pb).

our

(w

of

(dashe

10

=

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al, resonac

they

4He(y, in

a functio VeM

(dash- ot ed

exp rim ntal

pf

giant

section,

section

MeV.

as

01 =

VeM

1.45 40

=

fp

enrgy

peak taken

inc de t curve),

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for

from

(triangles).

pf refs.

the region.

and

reheigt

1.53

whic

curve),

to al

In

separ tely

4He(y,p)3H.

decay)

yb

1 mb si c o r e t ,

f I this

SUM ARY

4.

eW

would

phot dis ntegration

The

02

In have

this

pn) Specta o,

pa er, invest ga d mechanis

ew result

and with

fo

deut ron

have both to

invest ga d

4He(y, describ

reactions

exp rim ntal phot dis ntegration.

the

pn)dS ecta or using the

phot n

data.

phot dis n egrat o whic

evah a ingles In t h e absorpti n eW aveh

theor ical model,

ben

reactions observd

introduce

amplitude

ew

model have

yb using

and

as umed the

relativ

the

TAGX compared the

group. exp rimental

the evaw

the quasifunc-

at

182

tion space sy tem observa l directly. fit

betw n

to

pn

the

integra ion

to

compare The

the

in

entir final

data

fo

pair

careful y

deuteron

with

and the

en rgy

state

the in region

interac on

specta or

orde

data.

fo

phot dis ntegra ion.

to Using

particle

cal u te

the

inter s si p a r t l y

Our model si found t o rep oduc the descr pan i remain. Thes descr pan i cros section for 3He(y,pn)ta and f o 4He(y,pn)d ta , reaction around are ifcultd t o rep oduce with the pres nt thes discrepan nvolei important fo the phot dis ntegra ion reactions be treated carefuly. orF the 4He target inclus o f o large er o rof some parts roF further studies, ew ned t o devlop functio s fo the in t al and final sta es in orde t o understand thes reactions cal u te the bservalo ni a suitable data. eW would like t o thank the TAGX

and

include gros

-

(i )

7E informat 3He fo

exp rimental

pres nt

featur s

4He

phot n

using

group

target

theor tical compare in

eW and

the

on

the

step-lik

the

rof

that

of change

exp rimenal ew

ew

the

that

can

deuteron based

think it

with

Thus diferncs could

discrepan

but

fo cros

very

on

and

compare

certain

that should

due

to

the evaw

cur ents

important

with

discuon.

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J . Nucl.

JETP Balestra

Lebdv

(1958) et

Rev.

Let .

627.

Phys. Phys.

693.

(19 )

10

34

109.

(19 5)

al

Nuov

87

Inst.

(19 7)

60;

10

(1970) 71

A.

.N

(1974)l.

Cim.

4015.

the

to al

section betwn

ac ur te to

data

the beliv

be

si

model

cal u te used

ew

hadronic

phase

have

to al

thes

the

co rdinate

data,

the

model

stimulating

the

dep n ce

model.

es ntial

treated

a suitable

since

fo

eW

microsp

model,

exist ng

found

data. interac ion

deply.

the

en rgy change

and in

with

model al

MeV.

eH

the

of

the

(i)

step-lik

and case, a microsp

the observal

can

150

phenomlgica

and more

form

the

are

in

the

639. Gor-

38A

to

Hadron K.

dna Maruym

a 02

Nuclear and

Elsevir

Physic

H. Scien

Two-nucle

lA

Probes

rights

resvd.

der

mechanis at resoluti n

Insti ut Morgenstl

:s erd a

emison

ac el r to

phot n

Univers ta

D-6702 .physik.uni-tuebingen.de

Tubinge ,

Tubinge ,

exp rim nts MAI

absorption. distance

and (7,)

mean en rgy

the

back

than

field revald

[1,2]

05

the

conti u m

creation Thus

one

Pauli

The can

Maim

at Evidenc

si exp rim nts (e,N)

perfomd

Germany

Mainz

are

rof

pres nt d.

with discue.

real

efcts

The

due ned

si emphasi d.

and

eW

to of

nucleoa ombinedc

virtual have

phot ns

studie

the

an lysi

at

reaction

cor elati ns

the

of

hig

INTRODUCTION The

low-m entu ments traced more inter ucl o into repulsion scat ering; the princ le.

of

inter ucl o

der

14,

grabmy@pit

short

.1

in

at

a

Two-nucle cw-eltron

183

exp rim nts

Grabmayr

Physikalce fuA liam-e

two-nucle

B.V


emison Pet r

nucleo-

htiw

onukO

princ le

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dynamic l

observd

to distances

to

years

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or

cor elati ns

ago, at

the

smal degr

the more

the

conservati

with

poten ial Ther

:p

short

Cdyn

that

sta ed

distance short- ange contributed

this

deviat ons

cor elati ns.

%52 mean-fild

typical

relativ

pro e ti s Fermi

wories

namely,

spoil

wher

describ Only about

that

princ al

observ

to

around

a certain f o a n verag

density

con e t d

conept

range

inter-uclo

from of

centr-ofmu

are

are

in

fo

surface recnt

the

the

alre dy

strength

hig

conept

spectroy

one-particl

of whic

nuclear

si l e w feature the

the

sevral

mean

centr distance :

saw

at

mo entu

kinds

the

time

and

can ot yb

sta es

rep s nt

that know

al

nucleos

dleif

of

of

inter s

survie

misng.

has transfe

birth

they in

shift fre

hci w

triv al

are

and

nucleoin

and

behaviour

and

of

comp ne ts purs ed

be n

the

whic

cor elati ns

Im ediat ly

fo

anymore. atomic

ap rent

the

sup ortive

particular

exp ri-

this shel

strength

the

sucefl low-enrgy,

knocut

are include

in

rather clasi

at hig

The nuclei

saw model

short

strong

(N )

despit

as

the e.g

in

those

so-caled the

up

Pauli due

whic

fre

to

184

(se . tricate. stil H. the tion about culations difernt with type

The

e.g Muther

empir cal yield

bind g difernt

l ehs-f o

Recnt cor elat d

with

for

real

The

si

at

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theor tical only

bind g

with

play

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invest ga on the

point

a cru ial

invest ga on

thes

of

aim

[4,5 9].

the

poten ials

part part

evaw

towards

functio

fo

fo

thes in

cal u tions

two

whic

specif

ranged

bind g.

rof rof ben

tif

on

from

Simple difernt

from

mean

cor elati ns

efcts

in

A

bind g

found.

t h e phase si orlyp rof t h e

nucleos techniqus

based

short

evah

lpl 2

modern

a result @ si deriv

poten ials

into

poten ials. While

is extrac ed

the

ranged

nuclear

N

exchang 7r

the

short cor elati ns

poten ials.

nucleo

rof

Her,

of

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realist c

density

nuclei

incorp ated rof

ned per

fo

tensor

ben

treatment

argument using

evitc f

enrgy

contribu ons

behaviour

creation

and

cal u tions =

>

>

/V1

=

two-b dy

given

the

stronge

two-nucle

the

>

$21~1~2

,rev woH

have

the recnt modern

Brueckn-HatFo

np

the

uncor elat d

exp(S)-method

compilat n

nuclear

for

cleary rev woh

from

t o produce

scat ering

two-hle

tensor

[4])

l6O

for

, Q throug : one

at

cal-

ind cates

[4].

ref.

yb calu-

poten ials

N

-ni

mediu

mat er

N

chan el

(ad pted the

of Harte-Fock

ap ro ches si more

nuclear

This

shift defin,

dleif

spectral

func-

si nevig

[4].

operator

the QllVl

demonstra es

same

The

the

Lim t ng

saturation

the

quality.

.1

tions The

[4]

cor elati ns

[3]). of

from

the equal cor elati ns

ranged ref.

One

arise

Figure

wher

long

an ih l t o

y=O,

Fig.

The

fm).

>

$11~2

rof

two

z,z-plane

operato s cor elat d

the

> >

AQiIVi

.1 2=2

n=2

+SllVl

density

in

to

in

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si left

selctd

the

side

set

functio s

of

read

n particle-n

hole

sta es.

>

+ S 2 l ~ ~ 2

prot ns

On

produce evaw

(5) orbit

of

lplp

rof Fig.

O=y

of

wher 1 the

06l

operato

the

second

S2=0

particle

and

therfo

si dexif

185

the locati n density the but contribut ons.

two-b dy can

T=O also

of its

one-ucl

be

np

observd

pair con e tra ion

si second

just

particle).

revals

not

exp riments.

at

the only

at

product posit n

an

short

S2#0

roF interuclo

exp ct d

of of

the

howevr,

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densit

a learc particle. of s t r e n g t h despit

distance

(ir esp ct v

depl tion Simlar

yb large

TA

Figure perim ntal setup ger, doscpe Pip neutron thgilf- o ray kinemat c l gions cated.

.2 prot n

a factor

tag-

[l ]

AND

VeM

at

relativ

esolc

reactions,

hig

reaction

the

resoluti n

of

as

wen models

(y,np),

VIRTUAL

4

had

reactions.

(y,p ),

PHOT NS

ar-er

at

Mainz

of using

the

PiP/TOF

the

wogsalG iN

group

tag in

are

perfomd

imp nge phot ns

on

at

spectrom

4 pm thin radi tor ro on 0 1 polarised are ne d . The phot n beam si colimated (diamet r of ap rox. 1 , 5 cm) on t h e uclearn targets with n a kapton can or of shet f o graphite ro l i t h u m . t o fre run i g calers with n the tag er ocalf plane surem nts. Typical aluesv of ~ ~ = 4 5 & 2 % evah enb yb a ring fo 1 m thick plastic counters, hci w act as and a s veto det c ors rof neutrons t o b e elctds from

85

rof

two-nucle

of

ind-

[14]

REAL

the

the

about exchang

-oh

Thre

exp riments

WITH

fo

meson

,rev woH

area, and

of

two-b dy

and

time-

are

The

MAINZ

pairs

cal u tions

cor elati ns

induce

the

Ex-

with

[12].

in

This

EXP RIMENTS

2.

MAI

removal

the

si n o t a n adequate to l one has t o invest ga exp rim ntal method rof a n aces towards be n sug e t d alre dy ni t h e 50-ies, ni particular pion and phot n Both probes are understo d t o be absor ed domina tly on nucleo proximty [lo]. Howevr, beam quality, nergy resoluti n and background e.g the not ri us final-st e interaction, revntdp seriou proges. gen ration f o exp rimental techniqu s rof w c ac el r to s and large det c ors on one ides and wen devlopmnts of uclearn structure permit a renwd ap ro ch towards N cor elati ns. The aim of t h e pres nt exp rim ntal seri si a ombinedc an lysi (e, np) and (e, p ) t o exploit the adv nt ges of each of t h e reactions. removal

sA

density

the

pm

thick

hci w yb

the

consit

obtained.

in

The so-caled

start

[15].

TOF[12].

det c ors

phot n The

wc diamon

orde

el ctron

ac el r to

Electron to

eith r

flux

tag in Charged

target rof

be of

charged

ycnei f

crystal liqud

Figure Layout

3. the

thre spectromet r facilty ]31[ Mainz.

at

beams

l ew

defin

is

calibr ted

is

sur o nde particles

in

of case

helium mea-

particles

are

186

exclusivy

det cted deuterons in

by air

by

sel ct d tion azimuthal facil ty so-caled

TOF

by

(Em) The

dead

with

160(e, p )14C [13]

fo

super- a l e

from ap ropriate

direct on

fiveold

pions

the

layers.

an

via

6 VeM

with

the nucleo

The

layerd

the

hig

pulse

heig t

- E technique.

The

neutron

en rgy about

after

Pi [1 ].

relative

thre

observa l mo entum

s i defin

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OF fo

as

the

4.

12C

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ranges

fin

(y,np) 4He.

The

pro e

MECHANIS

difernc

importance

betw n

and

fiP:

(PWIA) p , can be interp et d I t governs the gros featur s fo The mis ng en rgy Em = k -T, particles in t h e in- a n d outg in ( A - 2 ) sy tem f o the recoil ng mo entum is efind a s fi? = a handle f o the relative mo entum get

Figure phot n targets

hod sc pe

AE

Prot ns

en rgy

cor e ti n is o b t a i n e d fo 0 . 7 ns. The FWHM cuts on pulse heig t vs. ime-oflght. has be n obtained. The angul r resoluti n can be translated into a mo entum exp riments with virtual phot ns (140 PA). A waterf l beam cur ents kinematics asw sel ct d [17], hicw

aver g

REACTION

3.

&,

and

the

and

is

reaction

compared

fim

the

betw n the

;(Cp

are two

=

as

-Tp

nucleos

incom g

+

the angul r

the

F,). -

for

,p

and

thre

the

In

en rgy,

P fo as

the particular,

that in t al

the

Figure phot n targets

the

discr minated

the of

employ

particles

An

particles

and

time-oflgh in of

the

polar 35

thre [16]

was

A

lose

measur d

TOF

en rgy

MeV/c.

ag inst

is e x t r a c t e d

en rgy in

overal 3

target

ther

C

5.

dep n ce

wave

the

The

from

The and

mis ng

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resolu-

fo

spectromet r

can

be

9

used

cur ents.

pair

p,.

is no

ranges

befor

TR

fo

modelfr

(y,p ) 4He

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impulse

difernc

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the

pair.

mo entum

plane

In

relativ s c l y

quenchi g

sup res d

fo

en rgy

si defin Note, in

phot n

fip. -

chan els.

resoluti n

are

thes

in

and a

REACTIONS

misng

mo entum

-TR

rof

(7,)

k - fin

reaction cal u ted

for

THE

from charged

of

.

fo

and the

the

kinet c si t h e Final y,

is

reaction

the

ap roximat on

outg in

interac ion.

cros

section .

en rgi s

kinet c pos ib l ty

compared

and

mo entum

the

relative

for

fo

en rgy

for

to

thre

the

187

son enrgy The can arise (el50 state permit

An

be

bins

C"

sta ed. from

In

data

of in

numbers

6.

two-b dy for

con e tra ion

N

misng

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the

the

contras

picture

fo

the

MeV)

interac ions.

treatment of t h e comp ne ts genral quantum

Figure E,=(135&20)

overal

[18, 9 7]

the

cor elati ns

si 4He

two-nucle

in

unexp cted

It

to

of

dat

the

the

l ew

enrgy

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angul r

vari t on

can

Angular

wol knocut

distr butions

on

the

of

sta e-of the-art

cros

angul r [23].

si overdc (se si cleary bservd.o 6 t h e counts aveh The thin solid section for photdisnegrato f o the n p pair of mediu the simple quaside t ron

reaction difernt

becaus

of

VeM

to

the

Fig. ben (dot- ashed) with n modifcatn

Valenci

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enrgis

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cal u tions

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12C(y,np)

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throug

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enrgis yield

Ex

recognisd section ,

roF The

C21

si o b t a i n e d model

reaction phot n

proces.

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distr bution With

of

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at

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absorption

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Next, e w focus and a t E,=(135120) relvant phase space neutron and prot n in t h e right of Fig. selg longa the ridge. exp rimental cros ering ermiF moti n data si a clear ind cat o proces beyond

relativ

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be

yb

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spectra

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describ observd

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competing

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to

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hig

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as

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Prope

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ind cates pair

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of

yb The

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residual

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hadron mas e and coupling condit ons. The separ tion radius, fo the equil br um radius the derivat es a t T O fo TO, W%(TO)) = 0 . Using with some precis on, giv n model, but not orf the domain. The Cloudy bag detailed tif t o N data

by

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ro

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with ruling =

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fo

1.05

Eq. lat er out

asympto ic (1)

first fm.

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also

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lat er

the

distant

model

given

fixes for with

derivat es

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or

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at

poles

experiments

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becaus

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a, W vanish g functio

with

constant

indep nt

the

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coefints

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591

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and

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DE U T E R O N

3. 3.1.

Interior

The

Becaus

each

In

other

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evaw

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with

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to

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=

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core

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07.2

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to

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NS1(650)P

GeV.

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in

the

ben

si

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fo best

exotics.

for

the and

The

than

exchang

of

resona c ,

other

models

f$

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+1

=

produce

the

at

types large

are

with to

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the

include

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rg,

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al But

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the

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fap,

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v(~D~) A

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to

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to

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sector sector .

ratio

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is

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our

chan els,

arise

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our

quark

ther

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as

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in

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W,

models

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exotic

that

being

a sub tan i l

also

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the

the

si lsoa repulsion enrgy

as

[q(lsa)l6

of in

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in

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so

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at

q .f de

poten ials

configurat , width shown[l ]

the

be n

proba il ty

a argel of t h e this

of

tensor

has

resulting

and

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As

the N scat ering data, a tif t o t h e np(3S1 -3 Dl) phase par met rs 6 and sector requi s and 1 rof 5 0 . 8 GeV. roF the odelsm C and 0 [12], hci w evah chan els. t h e rewol nergy behavior of t h e s6 and 1 det rmin the the enrgy dep n c rof 0.4 GeV < ,& < 0.8 VeG sexif those LIA(~S~) sectors, and the N t o t h e sum of A ( 3 D 1 ) and A(D1) two evah the same thres old behavior, fectinga the elastic scat ering os t h e ratio Only detail d A-production data could separ te them, edf . The magnetic form factor -depncq si very senitv to the op site spin and conveti cur ents of thes sta es[6]. The

than

[q(ls;)I6

actu l model

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k[

AS31( 620) P

imples

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rof

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N *(14 0) 3S

the

cores

functio s

yb

strong

other

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a pro e ty In our at T O .

the

evaw

N meson

importance and

thre

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of

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increas

have first

the

rof

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states

modify

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can scat ering

=

isobar

N

times

function PJ

be

of

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above fa@

to

2-3

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corespndig GeV

the

in

si

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sy tem,

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large

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EN 0.76

GeV, vanishe

hard change

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De t e r m i n g

state,

estima ed

0,

to

its

function the in

+1

ALI(~S~)

and

contribut ng and range NS1 (153 )(lp ), Thes neglib 3.3.

Exterior the

A (3D1)

and

cor esp nd

PREDICTIONS

the I = 0, J P = resonac si only inter o evaw functio inter o has be n evaw function, in t h e fectiv from the rapid matching fo proba il ty and The fact that pensated yb t h e efctiv range models difer at 3.2.

W,

while

N

of

to

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and last the the

691

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ecioh

=

TO

to

fo

1.05

the

model

separ tion mf

s6

C

di

as while

case

not

radius

discue

consider

quark

saw

above.

ro

=

As

D si a b e t e r

0.74 shown

tif

fm. to

configurat s[l3]. previously[ 2],

5

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Col ab., Col ab.,

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Martin

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A. Group,

9-038,

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et

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at

et a l . et al.

, DESY-9056,

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Phys.

Phys. Phys.

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to

wM

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J. J.

J. Finla d.

107.

.7642

t-quark, solid

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AMz)

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the

yb

namely

nwohs

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, DESY-9107,

that

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obtained

REFERENCES 1.

First,

as

GeV. above)

saw

as umptions.

yb

GeV, double

(theo.)

the

theor tical extrac ed yield

GeVf3.7(theo.)

H1 a Standard

The

The MS obtained

the

=

and bosn

2

muon-decay

shown

wM 80.9zk3.3(stat.)i1.7(syst.) MS

perfomd of

81.4T$:i(sta =

H1

line.

The tions

er w

Finla d. Finla d.

saw

the

Hadron

K.

and Maruym

02

on

Scien

with Okuno

B.V

Sakemi"* of

the of

positr n and

asym etri on

1 GeV2 z rof up

polariz t on with hadron GeV/c typical arise

zero.

charged

pairs

the measur d

,

from

lA

Probes

sthgir

29 resvd.

nucleo

studie

SEMR H by

col ab r ti n

Physic ,

Toky Meguro-k, of

hadrons

polarized

and

Electromagni

HERM S

1 Ookay m ,

Spin

(Editors)

the

fo

behalf

negativly

sci yhP H.

structure

"Departmen - 2 12-

of

and

Elsevir

Spin Yasuhiro

Nuclear

semi-ncluv

< 10

< Q2

down si negativ A measur nt si lsoa measur d

in

de p gluon

the

The measur d of

asym etry polariz t n.

of

5 8-2 1 cros

be n

and

. Polarized

GeV2 in

pres nt d.

a positve

have

hydrogen quarks.

Insti ute

oyk T

3He

roF

si

inelastc

h+-

range.

distr butions

polariz t n

asym etr

dep-inlastc in

rof

from

with

contras

producti n

kinemat c polariz t n

in

the

the

The

pairs

negativ ,

scat ering

in

targets quark

quark spin

Japan

,1

section

measur d

up

the

Technolgy,

are

s i positve in

lkp

the

>

prot ns,

extrac ed

of

1.5

to

and

the GeV/c

the

of

0.23

of

phot r duction

positvely

scat ering range

can

and

down si compatible and

positve

< x < 0.6

as

the

sea

be

a functio fo

asym etri

interp ted

and

polarized

pk2

quark hig-pT

>

1.0

to

INTRODUCTION

.1

polarized the

The

HERM S

de p

nucleo

exp rim nt

inelast c may

be

studies

scat ering decomps

the (DIS). as:

spin In

the

structure

the

fo

Quark-Parton

nucleo

using Model

semi-ncluv

(QPM),

the

spin

of

wher

)1(

and and Ax whic

Previous

distr bution

*E-mail

AX, gluon

orbital

betw n

Au, =

AG,

,q L

valenc

inclusve

can

ad res :

be

and

+

+Ad,

functio s

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pj.ca.hceti .syhp.lcun@imekas

LZG mo entu . sea

and

angul r

+

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are

the

XA

contribu s: Ai +

in

contribu s

+ Ad,

the

precisly

Aq

can

QPM

Ad+ as

E

(qf(z)

be

measurd

As the -

sum

q-(z)):

from

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+

dive

quark

and

among

gluon

spin

the

quark

and

quark flavors,

Ag.

revo

the

polarized

(2)

al

the

flavors

structure of

polarized

functio

parton

g1

(x),

032

The (anti-par l el) charge. scat er d and

function, Her , en rgy

)z(1g

from

a third fo In t h e scat er d virtual phot n final state. the ind v ual det cts the whic are One yaw fusion diagram. dijet production. the cent r PT hadrons dep ndent gluon distribution This pa er the HERMES in t h e HERA from the

THE

2.

27.5

qf(-), rep s nt t o the nucleo z is t h e Bjorken lepton’s kinematics, f o the exchang d various targets the nucleo spin, semi-ncluv measur ments, lepton. Hadron yb a point-l ke Measuring asym etri s contribu ons properties f o the cor elat d t o the t o measur AG(x) In de p Jet separ tion f o mas en rgy instead f o jets. hig-pr hadron AG have reports on t h e exp riment storage ring spin asym etry

[4].

The

HERM S The

HERMES GeV

is n a t u r a l y sion f o synchrot n point si provide during the % (3.4 %) The HERA contai ng metas bil ty-exchange certainty sextupole Breit-Rabi run. The HERMES ing chambers

exp riment

the

spin, virtual

and

and productions

integra ing

that

of

not phot r duction

in

fo

the

yb

DESY,

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DIS

the

flavors

hig

fo

27.5 hadrons.

and

sub eq nt

one

quark fo

the

at

enough.

GeV

polarized on

[ l ] [2] 3 .

can

breakup in most

quark polarized

fragmenta ion

the

rev woH

do studies

of

yields reaction.

this fixed

orde

the further the

via

charm

distribution gluon

distribution

yB

AX

polarized.

coin de

thes

after

four-m entum

reactions,

par l e

el m ntary

is only

by

the

measuring

about with

absorption into

ins ght

QCD

phot n production

gluon to

due

use

t o the

from polarized

a

into also

one

scat ering,

the

fo

a hadronic

in t al

target exp riments i t is pos ible f o the sen it v y

el ctrop duction

longitud nal y

in

spin

the

mas .

that with

In leading

squared

found

negativ ly

AX.

low-Q2

beam the

nucleo

q with units fo is d e t r m i n e d

in

whic

negativ

reactions

to nucleo

and

the

charge

Q2/2Mv

flavor of

M is t h e i t has be n sea ems are measur d are describ

5,

posible

condu te the

v are and

the

struck

isolat n

phenom l gica

hadrons

quarks

z =

strange

semi-ncluv

quark

scat ering, is not

be n extraction at

of

in of

being wef A

and revo

and

fo quark

si t h e

the

the is

,e

vari ble

Q2 phot n,

inelastic

using

and

scaling

quark fragments

flavor

wher

distribution

polarized

data

positr ns extracted

hig-

fo

or to spin-

taken

yb

EXPERIMENT exp riment

saw design t o optim ze semi-ncluv DIS measur ments is located a t the DESY laboratory in H a m b u r g , Germany, positron ( o r el ctron) beam si cir ulated in t h e HERA ring. The positr n polarized transver t o the beam direct on due t o a n asym etry radiation, and longitud nal polariz t on at t h e HERMES by a pair of m a t c h e d spin rota ors. The aver g d beam run si 5 % w i t h a relativ sy tema ic uncertain y in t h e measur ment for t h e 3He(H) data. beam pas e through the cent r f o a 40 cm long cylindr a polarized 3He or ’H. I n 19 5, the 3He target atoms becam polarized a fractional optical pum ing [5]. Polariz t on si 46 % with and 19 7, a n Atomic Beam Source (ABS) used f o 5 % . I n 196 magnets and radio-f equ ncy units t o selct desir hyperfin sta es polarimet r (BRP) monit rs t h e prot n polariz t on, whic is 86 % placed

det ctor

befor

is

and

an

after

open-g m try

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magnet

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det rmine

spectromet r.

mo enta

A

seri

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the

interac ion

a

beam emis-

4.0 of

storage

cel

through permane t

fo

during direct ons

fo

un-

’H.

the track-

A

23

of

those Preshow

particles.

from menta polarized data

hadrons.

of

ROVALF

In

Under directly to

wher

and negativ actions Inclusive and sati fy ng The and able.

in

tion

signfcat

The

rep s nt

H’

to

Cernkov 3.8

si

study

thres old

and

an

GeV/c used

the

Cernkov

Electromagn ic to

gluon

furthe

in

extrac polariz t n,

det c or,

195

provides

and

polarized

par l e

Spin

asym etri and

as umption

relat d

structure

D. .y

structure

hadrons

HERM S from the

W2

an lyzed

measur d 195,

kinemat c

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are

and

Interp a ion

yield

the

measur d and

asym etri the

Q2

proba il ty

dep n c .

state

sel ct

target

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196,

requi m nts

fluct a ion

are

ratio,

selctd

asym etri

on

197

the

evnts

the

as umed that

helicty

The

run i g. from

W2

the

nucleo

the

the

inclusve

er w

hadron ni

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fo

si

factors. both pions

mas ,

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beam

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to

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measur nt

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in

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particle polarized

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POLARIZED

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BUTIONS

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Figure

respctivly.

the

the

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8.0 0.6 0.4 2.0 0

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Figure .1 Results for the virtual phot n asym etri s 197 data. The top owr hows the asym etri s on the 3He target. The columns are the inclus ve, semi- nclu ve asym etries from left t o right. The inclus ve asym etri s El43 6][ a n d El54 7][ m e a s u r e m n t s . orF the semi- nclu ve a comparison with the SMC 8][ r e s u l t s a r e shown.

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wol

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PHOT PRODUCTION

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Table. 4.

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values

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Riad Col ab r ti n,

at

under

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prot n

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the

grant

rof

the

Universty DE-FG028ER41.

figures

02t

form of

bins

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factors, Col ab r ti n,

Q2 in

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weN

.x

Mark

and

This

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pres nta ion

the is sup orted

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REF NC S .1

620-19E

2. 3.

J . omez.G L . C.

4. 5.

E94-018

E93-027

Transfer D. A b o t ,

Measur m nt Alexa, Measurmnt

fo

Electri

in

et al., et

D(e,d)

al.,

the

form

Phys.

ISN

Scat ering,

of repo t Factor

Rev.

Electri

and Let .

the 10- 2 NSI

Deuteron

of

S.

the

Magnetic 4731

82,

Kox,

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Structure (19) Tensor (ISN-Grenobl ),

Polariz t n

.esi B by

Functio s,

lioceR

G. at

Polariz t n,

and

Large to

Petratos, Momentu

be

C.

published.

Perd isat,

V.

261

6.

7.

8. 9. 10. .1 12.

13. 14.

Punjabi. M. E95-01 vers E94-023 3He( , p) 01 -49E nectio E89-015 Bagh ei. E89-017 Sealock). E89-027 Boeglin. E89-031 tromet r, 230-98E Nucles

V.

15. 16.

E89-036

Phot n-Nucle s Detec or, E98-104 actions

K.

Jones,

e t al.,

Precis

Asym etr

Measur m nt

in

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pre int

AT

from

Hal

F.

A,

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of

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published.

D. Branfod

the Mat er

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3He

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LAS,

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Backwrd Holtr p,

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INTRODUCTION 1.

Polarized

el ctron phot ns, el ctron polarized (or to

beams under

uncover Detailed

contribute

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phot ns construc ion)

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2.

are

with inte s y

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PARITY to

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+

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kaon

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rof

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264

linear y

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[2] If

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K be

pref abl

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sy tem

to

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tes

(6a)

(4).

The

and

(6b).

region,

slight y

above

REF NCES

the

.1 2. 3.

R.H Y. The

Yam guchi,

Milburn, evaw

Phys. functio s

Soryushi n-Ke kyu

Rev. rof

10

Let rs 4He

and

:He

(in

(1963) evah

Jap nes ) ben

75. kindly

25

(1962)

sup lied

47. by

Prof.

Y. Akaish.

Hadron

K.

02

dna Maruym

Nuclear and

Elsevir

Nuclear

Physic

H. Scien

with Okuno B.V

physics

(Editors)

Electromagni

lA

Probes

sthgir

resvd.

265

experiments

STB

1.2-GeV

with

LXS-Toh ku

at

ring

J . Iias gi Laboratory

of

The struct,ion conti uo s is a b o u t the pres nt

nuclear 30 -nIeV constructed Howevr.

fo

stretcher-bo ster

el ctron

to

experimental

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not

l)o st,er

storage 30 -MeV The In stored tag ed 1

the

ready

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Ins

for

fo

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beam

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Univers ty, at

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en rgi s

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Mikamine, Toh ku

up

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Univers ty

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MeV

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en rgi s

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physic

Sendai

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982-0 6, rec ntly

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Japan

si

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1.

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ring.

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producing stations, We

a

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INTRODUCTION

.1

niclea,r

Labora,tory

Nuclear

a future

The

STB

extracted

t he

The strdclier in the phot n

in

1.0 to

el ctron an

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comis n g

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project. ring

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saw

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MeV

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forced

The

University

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a GeV

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an

Toh ku in

1967.

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operation dev loped.

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EXPERIMENTS

2. 30 -I e\; el ctrons oc upies

ring physic

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factor).

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to

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ro m

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the target

heam station 1, t h e

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from 1,

wher

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26

prepared target

5 ,E

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other in t h e

Figure Suclear

stretched

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1.

The (1) (2) (:3) (A) (5) (6) (7) (8) Her .

around

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fol wing Study Study .!dutS

Stud>. Col ective lfechanism Search Study

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ring

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MeV) for

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Experiments

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RIA;\I

the

"B(e, ’n) i otion

fo elastic (e,e’p)

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fo subthreshold for escihtion fo phot -absorption I discus the pos ib lity proces ; Experiment D G R has be n found

in

the

IVQR

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reaction.

heavy

ap roved

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proces reactions

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of

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pion excite in

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heavy

pion

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tag ed

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experiments

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D L M

In "C(7.n) Teras w [l]. charge

(e,ro) 40Ca(-j,n)

reactions.

reactions. and giant exchange

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Laboratory

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physic

be n

(e, ’fis ion)

the

photon

en rgy

experimental

nuclear have

GR

tag ed low

is t r a n s p o r t e d t o an lyze

and

(3) in

and

1.2-GeV the

and

ring

a list

with

operation,

ring

Stretcher-Bo ster

is fo fo fo fo

experiments; mode the

from

spectrogmph

en rgy ro i

Science.

1.2-CkI’

for

en rgy

in

a

at

the

LAhIPF

phot -

two-

762

(Lo5 the pliot

Alamoi) piesent, o-absorption.

[2]. no

-

Two GDR

and

in

heavy have

at empts

ion

reactions reported

be n

Two GDR

no hp

d

DGDR

DGDR

z+,/

l;SEL/

GDR

I

through regarde Fig. (1~rot~oi -1ieutron) step thus, reactions. many siInult’aneously,

In

In a. t w o - p h o n

’.

phot n role

Two-phon

GR (b)

pion pe,ts-ovT

2(a), the

as

two-phon

X in

with phot -absorption

two-step first

excita ,ion

suc e iv the

strong phot ns.

phot -absorption pos ihle

GR

-

phon GDR

Two

the

state. excita ion

and

step

zTo(xf,

reaction excita ion

cor espondi g

GDR Coul mb Then

a two-pno n Thus. meson

ion

exchange

mechanism proces ,

reaction

in

cur ent

esp cial y

particle-hole can

of

to

intemediate

the

nucle s

state

for

(a)

phot n

example,

two-phon

states

can

absorb, one

excita ion

is

MEC

phot n

states reaction.

as

To-2

must such

states en rgi s

i s know

nucleus.

the

target

for

shown "can

the

1-oT

the and

reaction

T-)

(T+,

fo

the

fo (proton-neuteron) in

excited projectile

The

double

charge

reaction.

the

7r-)zt T0 2 GDR

be

pion

absorption

the

the

is excited, only question two-phon

the

(MEC).

reactions: (c)

For

the

Phot-absrpin

)c(

various

and

f o another (GDRgGDR) field betw en the target GR proces , howev r; t,he inter sting

To-1

T O

reaction,

excites

2+

T O

~o)ztlTo-l(iTo,

via

GQRorGDR

reaction,

excita ions.

to

states

phon

O+

exchange

particle-hole

up

Howev r, two-phon

’

excited ion

charge

the

virtual t’he

the

,+o

Heavy

states

heavy

double

the the

(b)

reaction )

reaction.

t’he

is

x-

( Z+,

2.

?

I

/

Figure exchange

-

GA?;IL[4].

and

observ

GDR

o+,

(a)

SI [3]

at to

in

example,

hig er

be

As

AT=l

is

to

be

play

shown

heavy

two

3(b). part

in coupling

a

than

an

be

second

In

nuclei

excita ion

excited can

particle-hole The

excitation,

nucleus.

Fig. take an

may

can

provides phot ns excit ng

important the

and,

oc ur?

of GDR

in

ion

a

862

escit,ation. phot n el ctric

is

I-.

AT=l

dipole

In

coupled

3( c)

Fig. absorption

state:

I EC’

with a -1 dipole

1-

nucleon studied plan ing targets cliange

For

tu-o plion the

and

coupled that

of

mechanism

GR

escitation Sl to

with i n nuclear

with in

resona ce extend niucl

bet er

nuclei. the

in

GR

with fo

in

measurem nts

el ctrons, As

nuclear statistics, or

nietl u

the

the to

GR

tlie

absorption

single

the

one-plion

"Ca(

,3.

1.2-GeV

tag ed

reaction sta ,e.

phon s while by

phot -absorption

particle-hole

phon excited

nucleus.

by

at

order

in

by

fo the

main

the Yam zaki

se

and

ES whether

(7.p71)

facil ty

inter st in

course

the

IVGDRSIVGQR

this

states

escite

the

"Ca.

cor esponds isovector

MEC

the

be

t>wo-phon neutrons

-1

and

regarde

may

reactions the

and

target

station.

of

the resona ce

symposium[6],

is

t’he former

behavior

expect

on

various

IXS. property

ew

fo eV\ nuclear

be

giant’

acts

can

One

As

should

the

neutron-particle

ineasuring

this

not.

beam

other

to

SCI OR phot n

to

incident

GR whic

BEAM

,*( . T I ) to

of

phon since

fo

nest

sect,ion escitation

1-

The

the

The excita ,ions.

two-phon

CIR ULATING

TAGX Figure

the

fo

7 .n)

one

in

cros

D G R

GEV pres nted medium

the 2+ is n o t

two type

escitecl

shown. the

phon .

and

mode of

shematical y

double

proces :

a 2+

iso caler

1.2 GeV

the

main

one

neutron-hole

state

the

(I\’GDR);

An

photo

is

with

Thus.

WITH esperinients

con ects

be coupled

resona ce

(Ii-QGR).

EXPERIMENTS

escitation whic

should

phon

tlie isovector giant quatlrupole resona ce a T-J+ (or T+J-) operator. state si t h e proton-particle prot n-hole tjp. The a s the phon escitation . I Suz li [5] predicted t o be a s large a s 8k(i.L’ t o o1m .e the t,wo-plion escape from the two-phon

3.

the

have

does

the are

as

t>o

269

In F i g . The photon placed scintil at,ors thin carbon is removed The el ctrons x 0 2 m ). long light i agi et. There. be n working SCIS ORS detector for charged they can The ient fo photon for lon- en rgy

3,

at

tag ing

the

placed foil

from

The

two

Each fihr.

system, 1.2-GeV

be

t,he experiment

large (Sendai part,icle placed quality

we

show

the

experimental

tem

is

now

area

being

for

inst,al ed.

1.2-GeV

The

f the bending magnet (BM4) i n a snial ro m in the bencli g can b e moved lcna set, at the beam the beam posit on when t,he el ctron emit ing phot ns are detected with one scir til ator si c o n e c t e d with a special Then, phot,omult,ipliers can b e placed target posit on fo t h e ta,g ed photon detector sy t,ems wil b e placed: one very wel in the ES f a c i l t y at INS for CsI Scintil ation System On Radiat,ion consi ting f o 20 pure CsI crystals. The detection, while the lat er for ^/-ray at the target, posit on fo t h e tag ed tag ed phot,on tem is now being examined fo t h e 1.2-GeV el ctron beam circulating is e x p e c t e d to start i n Yay, 20 , nuclear physics but also for G e V en rgy entran

the

fo

maganet. posit on

system

tag ed

consi ts

BTS

The

very

beam fo

photon ring

quickly:

experiments. radiator

and

fo

10 the ac el rated.

a radiator

made rac1it)o

plastic

is i n j e c t e d and t,he plastic scintil ators (5 light guide which couples to a,t a d i s t a n c e from the bending is & o u t 7.5 m from the radiator. is t h e TAGX sytem, which these 15 y e a r s . The other is c a l e d Search): a large scintil ation former system wil b e used maily det ction. As shown i n Fig. photon beam. together with t h e improvethe STB ring. The tag ed and, then, SNL wil serve not nuclear physics.

a

fo

x 3-m 5

has

3,

only

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02

dna Maruym

dna

reiv slE

Laser

Physic

H. Scien

htiw

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el ctron

T.

Hot a * Fujiwar a,f Kish mot , Miyabe’, Ookuma", Shim zu",

M. T.

M. H. H. C.W.

tering out

At the

Cent r Japan

High at en rgy *Cor esp ndi g

various

the

lA

Probes

sthgir

resvd.

Atomic Synchrotron

Sugay f,

S.C

H.

fo

fo

Energy

Physic ,

phot production

M.

Wangd

ew

C.

Radiation

Univers ty

Nation l

built

cir ulating

fo in

Universty,

and Wak y m phot n

el ctron

+

phot n synchrotron author.

beams

el ctrons

radiation E-mail:

(laser synchrot n pj.ca.u-ak so.pncr@at oh

60-852,

beam. thres old,

near

Toy nak ,

Inage, beamline A

facil t es

radiation

15-742,

in

phot n)

laser-induc

Nagoy

the facilty,

world

D. Seki’,

560-43,

sy tem,

Osak

Japan

Insti ute,

90-856,

N7S

5E2,

Univers ty,

Tokai,

Japan

Can da

Japan

Nagoy

Japan

Japan 350

Wak i",

Japan

Korea

263-85,

is utilzed [1,2]. enabl s

A.

Mibe",

Japan

Yam gat

Osak

with det ctor is nearly

Ooba’,

679-5143,

Japan

TA

by

el ctron

og yH ASU

641-02,

Sas ki’,

KimJ,

T.

Ibar ki,

45701,

Seoul

Chiba

T.

T.

Z.Y

Japan

Res arch

Engi e r ,

Matsuok ",

679-5143,

Taiw n

Sask to n,

Da,"Bt

Mihoga k , 658-01,

46-802,

S.

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"ios Y

Energy

OH

FACIL TY produce

M.

og yH Mikazu,

Yam gat ,

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Kyot

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1529,

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Universty,

Wak y ma,

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Athens,

Universty,

Changd,

A.

To yam h,

Yorita",

W.C

Kobe, Mikazu,

Taipe

PHOTON

en rgy

third-gen ration

Univers ty,

Universty,

ELECTRON

Matsum rak>c,

T.

Univers ty,

Osak Chiba

Insti ute,

Ishikaw’,

Universty,

Japan

Universty,

Yam gat

Res arch Coleg,

Sin ca,

Res arch

Center,

Kyot Seoul

T.

Osak Universty,

Ohio Nagoy

Nomachi",

T.

T.

Kona

Res arch

Academi

Asano’,

Iwat h, M.

Physic ,

Physic ,

Res arch

Y.

Rang charyul ’@,

Surniham ~’, Yonehar b,

K.

SPring-8

T.

S . Makinop,

Nakno",

Nuclear

3 1 - 9 1 19 5 , J a p a n f o Physic , f o Physic , f o Physic , f o Physic , f o Physic , f o Physic , of Physic , for I n t e g r a t e d Japan f o Physic , Medical cir ulating

Imai’,

T.

Ooshimaf,

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at Akimuneb,

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(Editors)

phot n , J.K.

"Res arch 567-04, bDepartment ’Jap n dInsti ute "Jap n fAdvanced Ibar aki gDepartment hDepartment ’Department JDepartment kDepartment ’Department "Departmen "Cent r 46-803, ’Department *Wak y m

fo

Nuclear

nm

laser

optim zed

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phot n

backs t-

to

car y

SPRING-8 backw rd SPring-8,

for

nuclear us

to

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the

scat ering physic

world’s

the

hig est hig est

studies

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latnemir pxE

Figure

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The

Laser

en rgy laser el ctron facil ty a t BL3 EP, ,I is c i r c u l a t i n g with the straight section. produces GeV phot ns The maximu en rgy wavel ngth. The LEPS 350 nm Ar laser. At q5p threshold. y p -+ the maximu phot n beam is i t s flat inte si y sufer from hig inte si y beams. Another feature is LEP is also polarized a t lower phot n en rgy. phot ns i n wide en rgy can be monitored on fo the beamline. When the el ctron beam direction. At 1.5 GeV) are within about 1 cm at t h e target The en rgy fo the sy tem. The bending f o recoil el ctron. The the downstream end layers f o 50 pm thick scintil ator ar y. Phot ns

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laser used is

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the

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result

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used

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to

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integrated eW

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counter.

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Figure sured

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hit the

reachs

01

multi-ne

beam tag er

found

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at

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saw after

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about reflctivy

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whic the

beam

hit the

2 x si

214

PHYSIC 3. At iment

the

meson

change

as

old

universal

be gluon

the

be

(VMs)

vector

[3].

exchang

to

glueba

study terms

of

meson In

the helicty

at

are the

of

as

proces

HERA

exchang

many

done

rise

understo d

exampl , O+

to

LEPS,

enrgy

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describ

multi-gon

yb

stage

is

strongly

si

the of

cros exchang

eg R section

Then

evah

amplitudes

4 phot production.

proces

the at

sup re d s i ainlym a t wol enrgy that precis .]6[ yB singu of difernt [7]. region

proces

i t si ugestd contribu on contribu ons

first

domina ce. framewok

hadronic

exp rim nts

proces due

can measurnt

theory,

ben

prosed

and

hig

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yb be

OZI

to

studie

si s c a t e r d

[4].

In rule

Pomern

polarized proces,

The

y fluct a es

that MV

includg

phot n

and

of

unpolarized

One

phot r duction

into

MV

hci w

introduce

5q phot r duction.

yb and/or S

polarized knocut

section

.]5[

of

the

si l e w yb Pomer n t o describ exchang

Pomern

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only

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discue.

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cros

section

target,

from

know

the

from

means

fo

that l iw

thres -

ew

a nucleo,

exp rvector

can meson

clarify

-xe the

the

As can

an in

DETECORS

4.

Si

Figure

surem nt vert x time-oflgh

The

4.

The

LEPS det c ors

fo

LEPS

the

det c or (TOF)

De0tce

pirtS

tengaM

Dielop

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q5

det c or

(SVTX),

setup

phot r duction wal.

multi-wre

si

shown in

in drift

the

Fig. chambers

forwad

4.

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direct on.

det c or

(MWDC),

It

si consit

design

a dipole

fo magnet,

for silcon

the

meaand

strip a

275

along

The

the

planes

dipole

magnet

beam and

(z

si 0 3 pm and enrgy s ol for located upstream The sen it v for t h e DC2 a n d DC2) ro ’u (for The TOF l aw of l aw consi t long. The tim ng The TOF start ring. sA a s t a n d a r d a flight length 2 GeV/c mo entum ben tes d separ tely integrated test roF other exp riments, det c ors f o 14 superconducting target .

at

has

openig

the

(S Ds).

SVTX (DC1) DC3) the

of

are DC1 5 planes;

In

has

from

at

lev.

an 3 m

this

the

up

from

thicknes

02

achievd. signal

12 x

the

K/T

separ tion

dipole

target.

of

z’,

lead

of comp ne ts

pole

of 2 SD and u ) si

each y , ’,y magnet. x 08 u (for

the

The

cm the TOF x

2 m

storage

magnet of

the

sy tem.

devlopmnt

the

wide 8 GeV

scint l a g

of of

consit

mc

y from

25

posit n

(z,

cm idew y , ’y a n d the

thick

RF

labor t y

the

z, , ’ z

det c or of

in

fut re

ben

length

SVTX

5 planes

and from

case, Each

"0 1

downstream

4 mc

Brems t ahlung

-

we

the

The

The measur

with

particles psec

and

cent r.

and

up

has

ring.

of

The

laser

inte s y sy tem phot production

a

has

l iw

el ctron

produce be n

be

increasd

phot n

at

beam

a ylwen

up

construc ed si plan ed

devlop

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ben

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$ of

REF NCES .1

A.

2. 3.

C. T. (1978)

4.

5. 6.

7.

An

fiber Also,

polarized

to

SUM ARY

5. cesfuly

has 135 cm ediw and 5 cm hig si 0 6 c m . The dleif strength si 1 T y ) of ingle-sd silcon strip det c ors the strip pitch si 021 pm. With the particle ident f ca io . A MWDC and a pair of MWDC (DC2 and x 0 3 cm hig rof area si 08 mc wide DC3. Each f o the DC2 and DC3 the DC3). si used t o measur times of flight 0 4 plastic scint l a or bars of dimenso: resoluti n of b e t e r than o = 01 signal with 0 = 1 2 psec si made setup, the TOF l aw si located 4 m. of a charged particle si a b o u t si exp ct d a t bet er than 4o LEP beam and yb using the of t h e det c or has be n just started. a phot n calorimet , made radi t on lengths, covers from 03 solenid magnet si being built rof

M. Nucl.

A. .M A.

Scientf,

T.

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2 192)( D. R . einY

Col ab r ti n],

S. N .

Phys. Excit ng Yang,

Physic Phys.

Giordan

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and Phys.

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with

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and

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(192) Acelrato

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952

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(196) Faciltes,

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50,

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REF RENCES 2.

least

condit s,

in el ctron

the

at

be

thes

stored

Am-0 5

espcialy

and

should

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ThisPageIntolyLfBk


592

List Abramowicz,

Tel Halin

Akaish,

vi A

Asakw,

Universty

Cheon,

gnoT-1

Yonsei

Chiba,

Junsei

KE Tsuneo

En’yo,

Fries,

Kyot

Hatsud,

[email protected]

Universta fo

Hirenzak,

Kyot

Le , Levy,

f o Toky Seoul Osak

Universty Tel

Earle Kazushige

[email protected]. ci,osak -u.ac.jp takeshi.omubr@jp

Yonsei

suho ng

Avi

Aharon Maed,

pj.ca,u-akaso.ics.syhp@otomisik

KE

Houng

Lomn,

jckim@phya,snu.ac kr

Universty

Takeshi

Su

Universty Universty

Osak

Universty

Maschuet Tohku

@Ins.toh ku.ac jp

pj.ca oyk t-u.s nc@am yat k

Nationl

Hidek Komatsubr,

kas gi

Universty Tad fumi

[email protected]

Universty

Chan

Kishmot,

[email protected]

Universty

Tohku

Jong Kohri,

Universty

Dongshi

Takeshi

@phys.nar-wucj

[email protected]

Metroplian

Taeg

Katym,

zaki

[email protected]

Toky

Jirohta

@ unh.ed

f o Regina

Mashide Kasgi,

hersman

Universty

Universty

Mo n

Hampshire

Universty

Garth

Inuzka,

New

Women’s Osak

ed.negnibeut-inu.kisyhp.tip@

grabm yr

pjca.u-ot yk.syhpcs,ybur@adustah

fo

Tom aki Huber,

Tuebing

Universty

Nar

juergn.fis@phykt-mcd

pj.ca.ukoh t.syhp.adbmal@tomihsah

Universty Satoru

Muench

Universty Tohku

Bil

[email protected]

HiroshmaUnvety

Tetsuo Hersman,

Technolgy

pj.ca u-ot yk.syhpcs.np@oyne

Universty Osamu

and

endo p j . c a . u - a m i h s o r i h . l p e h . n o t o h p @

Pet r Hashimot,

Agriculte

Universty

Technis

Grabmy,

Kim,

fo

HiroshmaUnvety Juergn

Jeong,

pj.ca.ukoh t.syhp.raelcun@abihc

Univ.

Satoru

Hota,

[email protected]

Universty

Ichita Endo,

@tan shi.ke jp

junsei.ch ba@ke .jp

Toky

Hideto

a1zt.ucd

yuki p j . c a . u - a y o g a n . s y h p . h t - c u n @

Universty Tohku

Masmi Emura,

halin @ ak ish

Nagoy Masyuki

Endo,

Universty

KE Yoshinr

Chiba,

Purticmns

of

Universty

Instiue

levy

f o Technolgy

@ phya.onseickr

@alzt.uci

lom n

[email protected]

@mitlns.mit.edu

296

Mart,

fo Universty

Tery Maruym, Masike,

Fuki Akira

Meyr,

fo Universty

Koich

Miyake,

Electro-Cmunia Women

Nakyoshi, Kazuki Nomura,

Tom Okuno,

ik n

KE toru.nma@kejp

Oyam,

fo Trento Universty

Ken

Pshenic ov, Rangchryul,

Chary Sakguchi,

Atsuhi Sak mot ,

fo Academy

Universty

fo

Osak

Sasktchewn

Universty

Toshiak

imekas

Universty Toky

ude.bsynus.scisyhp.cinot

pj.ca.u-aw zan k.s mbiehca @ot mak s

f o Technolgy Instiue

Kyot

ur.kstiort.rni.Ol a@vonhcinehsp

pj.ca.u-ak so.ics. yhp@hcugak s

Kanzw

Seich

Sciens

[email protected]

Universty

Akita Atsuhi

[email protected]

@p ar

Toky Yasuhiro

Sciens

[email protected]

Rusian

Koh

Sakemi,

Shibat,

fo

SUNY

flaR

Shibat,

Academy

f o Bon INR,

Igor

pj.ca oyk t-u.s yhp.lcun3kam yo

Rusian Universty

Ewald

@ scien.ut

nid alro

Toky

fo

INR,

Eduar

Sas ki,

[email protected] ys ti ech.a jp [email protected]

Universty Giusepna

Rap ,

f o Technolgy Instiue

@tanshi.kejp

KE

Orlandi,

Paul,

@tanshi.kejp

KE

Hidek

Paryev,

[email protected] isoyak n

Toky Makot

1 .sciehm-uajp

f o Toky Universty

KE

Kazuo

@ tanshi.kejp

nak@qws

Universty Scien

Kozi

Oka,

[email protected]

[email protected]

Ehime

Naki,

[email protected]

Universty

KEWDESY

Nori

ke.jp

otum

Kunih ro

Nik,

ytisrev nU

KiFK

Nagno,

.mhr-unibocde

pj.ca.u-ak so.ics. yhp.mk@ekayim

Musahino

Masyuki Nak,

[email protected]

osamu.nrit@

Osak

orij Y Muto,

mas ike@mvb. iglobe.n jp

Universty

Toshi

.tanshikejp

Technolgy

KE

Osamu

Murat,

maruy@esnl

Bochum

Osak

Motba,

Toky fo

Uni.

Yoichr Monmatsu,

[email protected]

Universty Ruhr

Wern

Indoesia

@nucl.phystieaj

ikas

Universty

@ed.physakit-ucj

Instiue

shibat @HL.r i kyot -u.ac jp

fo

Technolgy

shibat @nucl.phys ti ech.a jp

297

Suda,

fo Physical Instiue

Toshim Sugimot ,

Toy

Ueda, Ukai,

[email protected]

Utsunomiya,

Hiroak

Women’s

[email protected]

Pharmceutil

ytisrev nU

wad @my-phan . c jp

KE Sakue

Yamguchi, Yamguchi,

Yoshi Yamur,

Hisahko Yamshit,

[email protected]

Ehime Mashiro

Universty

Yamzki,

Hiroht Yamzki,

f o Toky Okaym

y 921

f o Scien Universty

Shizuoka

Cancer Tohku

Centr

yam [email protected] ac.jp yam shita@n rs.go jp

Universty

pj.ca.ukoh t.snl@ikaz may

KE Yuji

Toky Koich Katsuhide

pjca.u-emihe.ics. yhp.lswq@ugam y

Universty

Haruo

Yoshida,

[email protected] -wu.ac jp

Universty Meij

Yamd,

Universty

Kona

Yoshicka

.dpcehim-uaj

ukai@t nashi.ke jp

Nar Yukio

Yazki,

uedat m@ehi gw

KE

Umeot,

Ins.toh ku.ac jp

[email protected]

Universty

Kumatro

Wad,

tamae4

Universty

Ehime

Tamotsu

pj.ca.u-iuk f.ylp a.mutnauq@

sua ki

KE

Katsuo

suda@rik xp.riken.go jp

sumi@hs. irok u- .ac jp

Universty

Hirokazu Tokush ,

Universty

Universty

Tohku Tadki

Tezuka,

Interaiol Fuk i

Toshi

Tame,

Resarch

shojiro.sugimot @ke .jp

Hiroshma

Yoshi Suz ki,

Chemical

KE

Shojir

Sumi,

dna

HiroshmaUnvety

Woman’s

[email protected]

Christan

Universty

pj.ca.oykot-u.s yhp3tikaz y

pj.ca.u-amihsorih.lpeh.notohp@adihsoy

@tan shi.ke jp

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Hadron and Nuclear Physics with Electromagnetic Probes

Hadron and Nuclear Physics with Electromagnetic Probes

Lattice Hadron Physics

Lattice Hadron Physics

Chemical Applications of Nuclear Probes

Particle and Nuclear Physics

Nuclear and Particle Physics

Nuclear and Particle Physics

Nuclear and particle physics

Nuclear and Particle Physics

Nuclear and particle physics

Electromagnetic Probes of Fundamental Physics: Erice, Italy 16 - 21 October 2001 (Science & Culture Series: Physics)

Nuclear and Particle Physics

Nuclear Physics

Nuclear Physics

Nuclear Physics

Nuclear Physics

Nuclear physics

Electromagnetic Interactions and Hadronic Structure (Cambridge Monographs on Particle Physics, Nuclear Physics and Cosmology)

Electromagnetic Interactions and Hadronic Structure (Cambridge Monographs on Particle Physics, Nuclear Physics and Cosmology)

Electromagnetic Interactions and Hadronic Structure (Cambridge Monographs on Particle Physics, Nuclear Physics and Cosmology)

Nuclear Physics and Reactor Theory

Nuclear physics: principles and applications

Top Quark Physics at Hadron Colliders

Top Quark Physics at Hadron Colliders

Nuclear Physics: Principles and Applications

Nuclear Physics with Polarized Particles (Lecture Notes in Physics)

Theoretical Nuclear And Subnuclear Physics

Nuclear Physics and Reactor Theory

Advances in Nuclear Physics

Foundations of Nuclear Physics

Hadron and Nuclear Physics with Electromagnetic Probes