Electron/Hadron Physics in Korea (in a personal view)

방 형 찬

고에너지협의회 회서울대

상산 205Oct. 06, 2005

I. Overview/Electro-Hadron Physics II. Main Physics in Electro-Hadron PhysicIII. Physics at JPARCIV. Retrospects and Prospects

I. Overview/Electro-Hadron Physics

I. High Energy ; QCD Physics underlined.

1. Heavy Ion

1. RHIC ; QGP

2. LHC/Alice ; QGP

3. GSI ; QCD phase diagram, Compressed matter

2. Electron /JLAB ; Spin(nucleon) physics,

Hadron Structure function,

3. Hadron/Meson ; KEK, JPARC, SPRING8

II. HI/RIB physics ;

Candidate domestic Accelerator as a long term

Spin Physics at Jefferson Lab

• Probing quark spins inside the nucleons using polarized electron beam

• Measurement of spin structure functions g1(x) and g2(x)

• Experimental verification of various QCD sum rules

• Comparison of integrals with theoretical calculations

Role of Korean Physicists - 한국인 책임연구원 JLAB 실험 E01-012 ;Neutron spin structure functions at higher Q2 E03-109 ;Spin structure functions of the proton E05-1XX (approved Aug. 2005); L/T separation for quasi-elastic scattering PR01-016 ; Measurement of the neutron d2 matrix element

Two Examples of Sum Rules

•Significant improvement of errors for Bjorken Sum at low Q2

•First measurement of Burkhardt-Cottingham sum rule on the neutron at low Q2 region

Hadron Physics at KEK & Spring8

I. KEK Strangeness Nuclear Physics

- Hypernuclear Physics ; > Effective B-B weak/strong interaction

> 3-body B-B weak interaction- KN interaction and K bound nuclear system > Deeply bound dense nuclear state found > Pre-cursor kaon condensation(?) > Dense matter study

Role of Korean Physicists

한국인 연구책임자 주요 KEK-PS 실험 :

KEK-PS E307; Hypernuclea Decay

E508.; Coincidence meas. Of Hypernuclei

Singles spectrum in NMWD

Comparison of Angular Correlation of He and C

We notice that

1. We now know that FSI(He) not strong.

2. Then what are those in Ynnnbb(He).

3. R(np) enhancement in C over He.

FSI?

2. R(nn) enhancement over R(np) both in He and C

2N?

where R=Nbb/Nnbb

15 counts

8 counts

K- potentials and bound states

• Y. Akaishi and TY, PRC (2002) Narrowing mechanism: EK < threshold• TY and Y. Akaishi, PLB (2002)

proton data

neutron data

Mass spectra

nucl-ex/0310018

χ2/DOF = 28.52/31Gaussian center: 3140.5 MeV/c2Gaussian sigma: 7.3 MeV/c2Statistical significance:S/ΔS=120/32= 3.7 σ

II. HE monochoromatic γ beam

Study of Resonance and Exotic states ; Λ(1405) etc.

Penta-quark state search;

II. Spring8/ LEPS

Role of Korean Physicists

한국읹 연구책임자등으로 LEPS 수행중 실험 ;

Spring8/LEPS; “Photo-production of Λ(1405)”

Pentaquark +

Exotic

B

ary

on

sN

ew

S

earc

hes

J-PA

RC

Ou

tlook

nK+

0spK

Penta-Quark Search at Spring8/LEPS

Exotic

B

ary

on

sN

ew

S

earc

hes

J-PA

RC

Ou

tlook

γ

p/nn/p

K+/K0

MMd(γ,K － p) GeV/c2

Quasi-free and non-resonant KKp

Bump structure

γd+ (1520) @ LEPS

III. JPARC (2009 실험 개시 ) -

하드론 물리 연구는 향후 JPARC 로 집중 전략

빔라인 진행 상황 ; 2009 년 봄부터 핵물리 실험 수행 예정 기묘도 핵물리 실험용 K1.8 빔라인만 확정 기타 빔라인 논의 중 (K1.1/K0.8, KL,High-p, K1.8-BR)

2005 년중 실험제안서 공모하여 빔라인 건설 계획 확정예정

I. High Momentum Beam Physics

1. Direct proton beam

– Transversity from Drell-Yann process

– Spin physics (with polarized beam)

2. Meson beam

– Quark/anti-quark distributions of the meson from Drell-Yann process

– Transversity of the nucleon (esp. strange quarks)

3. Exotic Particle Search

Physics with Pencil-typeπ Beam

1. Hypernuclear Physics 1.1 GeV/c Meson (K+, π +)Beam line

Large solid angle neutron counter array

BB weak Interaction via Decay of Hypernuclei

- Three body weak BB interaction

2. K-bound nuclear system study

Pencil π beam for background free (π +, K+) reaction

Kaonic nucleus physics

Summary

1. 장기적으로 경쟁력있는 가속기 연구소 설립을 목표로 두고 .

2. 중기적으로는 국제적인 가속기 시설 연구에서 visibility 를 높이기 위해 노력한다 . 이를 위해 좋은 연구 Proposal 을 제출하고 성공적으로 수행할 수 있도록 그룹 차원에서도 노력한다 .

3. 이러한 관점에서 한국인으로서 책임 연구를 수행하는 연구를 중심으로 살펴보았고

4. 연구에 대한 전망도 이러한 방향에서 살펴보았다 .

5. 앞으로의 연구도 지도적인 역할을 할 수 있는 연구를 중심으로 그룹의 노력을 집중하는 것이 바람직하다는 생각이며 또한 이러한 연구가 순조롭게 진행될 수 있도록 하는 방안을 학계 차원에서 찾을 필요가 있다 .

Extra Slides

Proposals at JLab• E01-012

– Neutron spin structure functions at higher Q2

• E03-109– Spin structure functions of the proton

• E05-1XX (approved Aug. 2005)– L/T separation for quasi-elastic scattering

• PR01-016

– Measurement of the neutron d2 matrix element

Meson Beams

• Strange quarks in the Kaon beams can be used to probe strange quark content in the normal nucleons– transversity of strange quarks

• Meson beam on polarized nucleon target producing vector mesons– might be another way to access transversity

Transversity from Drell-Yann

From Drell-Yann• Using unpolarized beam and target• Measurement of single-spin asymmetry of the azimuth

al distribution of the lepton pair• Access another transversity of the nucleon, h1

⊥

• h1⊥ describes transverse quark distributions in unpolari

zed hadrons

DIS - The Bottom Line: DIS cannot measure transversity

- Transversity measurement involves spin flip - DIS conserves helicity of the constituents

An from pN scattering

• JPARC LOI03 will do the similar experiment at JPARC with polarized proton target

• With the polarized neutron (3He) target under development in Korea, we can measure An for the pn scattering.

Quark Physics with Meson Beam

• Mesons are composed of quark, anti-quark pair

• Provides significant amount of anti-quark for Drell-Yann process

• From the known knowledge of PDFs of the nucleons, we can learn about q(x) and q(x) inside the meson: quite unique opportunity to study meson PDFs

1. Spin Physics Overview

• Transversity from Drell-Yann Process– unpolarized: probe quark, anti-quark distributions– polarized: study of the transversity

• Asymmetry in p+N scattering– Polarized proton target (LOI03)– Polarized neutron (3He) target;

under development at SNU– Gluon spin content?

Hypernuclear Physics

II. Hypernuclear Physics at K1.1 GeV/c beamline

Current LOIs; 1. S=-2 sector Hypernuclear Physics; at K1.8 GeV/c beamline

Ξ –hypernuclei with (K-,K+).

Double Λ hypernuclei decay by sequential pion decay.

γ spectroscopy of double Λ hypernuclei

2. S=-1 sector Hypernuclear Physics; ΔI=1/2 physics ; NMWD of A=4, 5 hypernuclei.

Our Proposal; 1. “NMweak decay study of Medium heavy Λ hypernuclei

with (π +, K+)” - To pin down 3-body process in weak decay.

- To fully determine the NMWD branching ratios

of medium heavy Λ hypernuclei.

Status of NMWD of Λ hypernuclei 1. Issues to be solved ;

- ΔI=1/2 rule

- Asymmetry Issue

- 3-body process of Weak Decay;

Is there such an effcet?

How much?

Why 3-body effect is so strong that it is comparabe to 2-body effect?

- Branching ratios of NMWD; It has been so long since the first realization, but no one was able to determine it yet.

Γ tot(=1/τ )

Γm

Γ nm

Γπ - ( Λ pπ - )

Γπ o ( Λ nπ o )

Γ p ( Λp np )

Γ n ( Λn nn )

Mesonic

q~ 100 MeV/c

Nonmesonic

q~ 400 MeV/c

Weak Decay Modes of Λ Hypernuclei

Γ 2N (ΛNN NNN)

(1N)(2N)

Non-Mesonic Weak Decay (NMWD) & Issues

1. B-B Weak Interaction ;

Λ + N -> N + N (ΔS=1 B-B Weak Interaction )

2. Long standing puzzle on : Γn/ Γp (≡np ratio)

3. Final State Interaction : It seems one of the important elements to understand NMWD.

4. 2N NMWD: 3-Body Interaction Process,Predicted to be a significant component of NMWD, though not experimentally identified yet.

5. Asymmetry :

Hyp. Nuc.

Γnm Γn/Γp

BNL

5ΛHe 0.41±0.

14.93±0.55

12ΛC 1,14±0.

21.33±1.12/0.

81

KEK’95

12ΛC 0.89±0.

181.87±0.91/1.

59

Status of Γn/Γp long standig puzzle

Γ n/Γ pexp >> Γ n/Γ p

th(OPE)

~ 1 ~0.1

1. Γ n/Γ p Puzzle :

3. Recent Exp. Development:

p n p,n simultaneous p,n coinc.

~ 1.0 ~0.5 ~0.5 ~ 0.5

E307 E369 E462/E508

2. Recent Development of Γ n/Γ ptheory : 0.3 ~ 0.7

Singles spectrum in NMWD

p

n

π

K

Setup E462Setup E462/E508/E508(KEK-PS K6 beamline & SKS)

N: 20cm×100cm×5cmT3: 10cm×100cm×2cmT2: 4cm×16cm×0.6cm

Solid angle: 26%9(T)+9(B)+8(S)%

π K

Energy spectrum in NMWD

1. Sharp peak in Ynp(He) at Q value. FSI negligible in He.

. Broad spec in Ynn(He) FSI? No. π - absorption or 2N? π - can not make it broad.

Must be 2N effect!!3. Ynp(C); FSI is significant.

4. Ynn(C); Even further degraded. Again must be 2N.

Esum = En + Ep Esum = En1 + En2

QQ

QQ

Comparison of Angular Correlation of He and C

We notice that

1. We now know that FSI(He) not strong.

2. Then what are those in Ynnnbb(He).

3. R(np) enhancement in C over He.

FSI?

2. R(nn) enhancement over R(np) both in He and C

2N?

where R=Nbb/Nnbb

15 counts

8 counts

Mijung result for 2N

Summary on Hypernuclear Physics1. A series of Hypernuclear decay experiments, KEK-PS E307, E369, E462 and

E508 have been done at SKS for the study of decay width of NMWD.

2. We have measured the mass dependence of Λ lifetime, particle spectra, decay asymmetry parameters and coincidence NN correlations of the decay of Λ hypernuclei(He, C) resolving the long standing puzzles on Г n/ Г p.

3. The signatures of (2N)-NMWD processes were found both in the singles and coincidence data and all of them indicates fairly large Γ 2N comparabel to Γ n. This probably is the first experimental identification of 3-body weak interaction process.

4. But we still can not say much on each decay width of each channel of NMWD. It is because ot the large Γ 2N and its large error bar.

5. Need a conclusive experiment at JPARC K1.1 GeV/c. to determine 1) Γ 2N : The strength of 3-body decay process

2) Γ n, Γ p ; have to determine their magnitudes.

1. Target; Scintillator ; 2cm x5(?)cm

1. Need a pencil-like beam profile; Δx < 1.5cm, Δy<1.5cm, Δz~15cm3. Prefered full open 2π angle.4. Open target area in Z ; 1 m5. Use old setup maximally.

Proposed Setup for the measurement

“NMWD of Medium Heavy Λ Hypernuclei”

We may fill this angles.

1. Δx = 1.2 cm

Δy = 1.2 cm

L(flat) ~ 20 cm

D(Q10) ~ 1 m

This profile probaly would be fine for the decay meas.

Yield Estimation

Yield Estimation for same tgt and Nπ + of E508,

1. Nnpnbb=8, Nnn

nbb=15, NNNN= 7(3)

2. εp ~ 5 εp0 8 εp0

3. εn ~ (5/3) εn0 (7/3) εn0

Nnpnew = 5 (5/3) Nnp= 8.3 Nnp = 65 145

Nnnnew = (5/3)2 Nnn= 2.8 Nnn = 42 counts 84

NNNNnew = 5 (5/3)2 NNNN = 14 x 7(3) ~ 100 (40) triple coin.

300(120)

Γ2N with 15% error, not with 70-100% error!!

Deeply Bound K-Nuclei

Current LOI on Dense K-nuclear states; (K-,N) reaction (K-,π-) and (π+,K+) reaction

K-

K Atomic states

Nuclear state

One LOI,

but very inclusive one.

E1s1s

1s

}

E2p

wid

th

1s

[eV

]

-500 50000

200

400

600

800

1000

shift 1s [eV]

Dav

ies

et a

l, 19

79

Izyc

ki e

t al,

1980

Bir

d et

al,

1983

repulsive attractive

KpX (KEK)M. Iwasaki et al, 1997

=

- 3

23 ±

63

± 11

eV

=

407

± 2

08 ±

100

eV

DEAR

Kaonic hydrogen puzzle

s p d f

Stark effect

aT=0 =-1.7 fm

aT=1 = 0.37 fm Repulsive Shift

Status of the study of Deeply bound K-nucleus

KN interaction

• Before 1997: Confusing situation• 1997 KpX experiment at KEK; Iwasaki et al.

PRL(1997): K-p atom shift: “repulsive”,• Indicating the K-p interaction is strongly attractive• Consistent with the view that L(1405)is 1s

bound state of K-p• Atomic ground state is 2s bound state.• --->> Akaishi-Yamazaki constructed a phenomenological

KN interaction combining

1. Kp scattering length2. K atom data3. Λ(1405) as Kp bound state

K- potentials and bound states

• Y. Akaishi and TY, PRC (2002) Narrowing mechanism: EK < threshold• TY and Y. Akaishi, PLB (2002)

Kaonic Bound States

• Believed to be non-existing: G > BE• However, Akaishi-Yamazaki (2002) predicted: - K--p interaction so strong - strongly bound states - shrinks nuclei --> deeper bound states - deep enough: the main decay channel KN-->SN closed • BE > 100 MeV: narrow bound states• High nucleon density: ρ ~ (4-7)ρ0

- chiral symmetry restoration? - deconfined quark-gluon phase?

Diagram Kaon Bound System

ppK- bound system

- kaonic “hydrogen molecule”

2. Experiment

Proton PID on NC

4He(K-stopped,p) spectra

Semi-inclusive momentum spectrum

A significant peak structureExists just below

500 MeV/c,

on a continuum due to

1. Formation via

2. Hypernuclear formation and its

non-mesonic two-body decay Discovery of a strange tribaryon S0

proton data

neutron data

Mass spectra

nucl-ex/0310018

χ2/DOF = 28.52/31Gaussian center: 3140.5 MeV/c2Gaussian sigma: 7.3 MeV/c2Statistical significance:S/ΔS=120/32= 3.7 σ

Summary of E471 results

See analysis detail onhttp://chiral05.riken.jp/OHP/1705-Suzuki.ppt

K- 3He atom

~threshold

theory (isospin singlet)

E

What is the situation ？

theory (isospin triplet)

p nparticle (other)

observed (isospin triplet)

~ 2

00 M

eV

(isospin singlet)

(theory)(experiment)

Bin

din

g en

ergy

Summary on K-nucleus

These findings provide important information about KN interaction, and may provide important information to understand the dynamics of a dense system, such as a strange star. In such a system, a restoration of chiral symmetry can be realized, and quarks may be deconfined, which are more or less unknown as of today.

Current LOIDense K-nuclear states; (K-,N) reaction (K-,π-) and (π+,K+) reaction

III. K-nucleus at K1.1 GeV/c beamline

EXTRA OHP

Status of the study of Deeply bound K-nucleus

II. Kaonic Nucleus

K-

K Atomic states

Nuclear state

E1s1s

1s

}

E2p

wid

th

1s

[eV

]

-500 50000

200

400

600

800

1000

shift 1s [eV]

Dav

ies

et a

l, 19

79

Izyc

ki e

t al,

1980

Bir

d et

al,

1983

repulsive attractive

Kaonic hydrogen puzzle

s p d f

Stark effect

aT=0 =-1.7 fm

aT=1 = 0.37 fm

Status of the study of Deeply bound K-nucleus

III. Proposal for K1.1 GeV/c1. Proposed Experiments

S=-1 hypernuclear weak decay study with (π+, K+);

- To pin down 3-body process in weak decay.

- To fully determine the NMWD branching ratios

of medium heavy Λ hypernuclei.

π beam condition;

- Need pencil beam with 1 cmΦx10 cm(z) profile

- Can we get rid of the beam tracking? Maybe.

0.08 rad = 5.5o , No.

We need to close the slit to 1/5-1/10 of

the current design.

Means to cut down the emittance

1/10 to get rid of Beam tracker.

8cm

1 m

Δx

MeV8cosM

ppM

HY

KHY

E307

E369

E462/E508

Γ tot(=1/τ )

Γm

Γ nm

Γπ - ( Λ pπ - )

Γπ o ( Λ nπ o )

Γ p ( Λp np )

Γ n ( Λn nn )

Mesonic

q~ 100 MeV/c

Nonmesonic

q~ 400 MeV/c

Weak Decay Modes of Λ Hypernuclei

Main focus of this talk

Γ 2N (ΛNN NNN)

(1N)(2N)

Non-Mesonic Weak Decay (NMWD) & Issues

1. B-B Weak Interaction ;

Λ + N -> N + N (ΔS=1 B-B Weak Interaction )

2. Long standing puzzle on : Γ n/Γ p (≡np ratio)

3. Final State Interaction : It seems one of the important elements to understand NMWD.

4. 2N NMWD: Predicted to be a significant component of NMWD, though not experimentally identified yet.

5. Asymmetry :

Hyp. Nuc.

Γnm Γn/Γp

BNL

5ΛHe 0.41±0.

14.93±0.55

12ΛC 1,14±0.

21.33±1.12/0.

81

KEK’95

12ΛC 0.89±0.

181.87±0.91/1.

59

Status of Γn/Γp long standig puzzle

Γ n/Γ pexp >> Γ n/Γ p

th(OPE)

~ 1 ~0.1

1. Γ n/Γ p Puzzle :

3. Recent Exp. Development:

p n p,n simultaneous p,n coinc.

~ 1.0 ~0.5 ~0.5 ~ 0.5

E307 E369 E462/E508

2. Recent Development of Γ n/Γ ptheory : 0.3 ~ 0.7

Np/d

ecay

where 2N ; ΛNN NNN.

Proton Energy spectrum& Final State Interaction

INC

Np/nm ~0.4

Ramos et al.

Λ+nn+nΛ+pn+p

Sato et al., PRC submitted

2N)(1N 0.230.11

(1N) 0.210.09

0.60

0.87

pΓnΓ

INC

Nn=0.69

Neutron Spectrum

Efficiency

Np =0.401. n yield is directly compared with th

at of p.

2.

3. Simple number counting givesPRC 68 (03) 065201

Λ+nn+nΛ+pn+p

1.730.40.6940MeV)(

pNnN

0.372

1p/NnN

pΓnΓ

Comparison of Angular Correlation of He and C

We notice that

1. R(np) enhancement in C over He.

FSI?

2. R(nn) enhancement over R(np) both in He and C

2N?

where R=Nbb/Nnbb

5ΛHe 12

ΛCnp pair

nn pair

np pair

nn pairnbb

Preliminary Results

5ΛHe : 0.61±0.081±0.082 (E462)

12ΛC : 0.58±0.06± 0.08 (E508)

: (0.45~0.51)±0.15 ( E307/E369)

Γ n/Γ p Status

10 0.5 1.5

n / p

Exp.

OPE

OME, DQ model

5ΛHe : 0.45 ±0.11 ± 0.03±(E462)

12ΛC : 0.50 ±0.13 ± (0.05) (E508)

Singles

Coincidence

Summary on Hypernuclear Physics

1. A series of experiments Hypernuclear decay experiments; KEK-PS E307, E369, E462 and E508 for which our students have

taken leading responsibility. 2. We have measured the mass dependence of Λ lifetime and the full set of de

cay widths and decay asymmetry parameters of Λ hypernuclei resolving the long standing puzzles on Гn/Гp and αNM.

3. The signatures of (2N)-NMWD processes were found both in the singles and coincidence data and all of them indicates fairly large Γ 2N comparabel to Γ n. This probably is the first experimental identification of two nucleon induced weak interaction process.

.

Extra OHP

For the singles of E462/E508

5ΛHe (E462) Γ n/Γ p(5ΛHe) = 0.61 ± 0.081 ± 0.082.

12ΛC (E508) Γ n/Γ p(12

ΛC) = 0.58 ± 0.06 ± 0.08.

5ΛHe (E462) Γ n/Γ p(5ΛHe) = 0.61 ± 0.081 ± 0.082.

12ΛC (E508) Γ n/Γ p(12

ΛC) = 0.58 ± 0.06 ± 0.08.

Correction for Cross over recoil effects

Similiarly for the coincidence yields of 5ΛHe and 12ΛC (E462/E508),

β'n2rpr

β'prnrαnpNnnN

where β ’ is reduced β due to the

back-to-back selection.

5ΛHe (E462) Γ n/Γ p(5ΛHe) = 0.43 ± 0.12 ± 0.044

12ΛC (E508) Γ n/Γ p(12

ΛC) = 0.50 ± 0.13 ± 0.05.

5ΛHe (E462) Γ n/Γ p(5ΛHe) = 0.43 ± 0.12 ± 0.044

12ΛC (E508) Γ n/Γ p(12

ΛC) = 0.50 ± 0.13 ± 0.05.

Quark condensate as a function and T and ρ

M. Lutz, S. Klimt and W. Weise, Nucl. Phys. A542 (1992) 52T. Hatsuda and T. Kunihiro, PRL 55 (1985) 158

New Frontiers of Exotic Atoms/Nuclei

From outside to inside

* atomic states of X radiative transitions from outer orbitals * terminated cascade

From inside to outside

* nuclear resonance states

* still bound states of X

EXOTIC ATOMS/NUCLEI

Evidence for partial restoration of chiral symmetry in nuclear medium probed by 1s pionic nuclei (2003)

b1/b1* = fp*(0.6r0)2/fp

2

= 0.78 +- 0.05

<qq>*/<qq>0

~ 0.65 at r=r0

The 1st clear support for the whole scenario: quantitative agreement

with theoretical predictions

isoisoso

Isovector s-wave N scattering length

eV)100208407()1163323( i

eV)30111249()637194( i

DEAR @ DANE

K X-ray1S

2P

4-3. Classification of the momentum spectrum 2

- VcaVp selection

Under pi-cut condition-(a) VcaVp : -6 ~ 0 -> hyper nuclear two-body decay

(b)VcaVp : 0~+6 -> hyper nuclear two-body decay

(c) VcaVp : -60~-6 -> Formation of a strange tribaryon and its non-mesonic decay

(d)VcaVp: 6~60

-> nothing to generate mono-chromatic structure…

4-5. Summary of the analysis

a): event topology of hypernuclear cascadeb),c): indication of analysis 1,2

2-2. kaon beam line Secondary K- beam extracted

through KEK-PS K5

* 2TP(Tera Proton)/spill(1.6 sec duration with 4 sec cycle) * 6cm thick Pt production target * pK

~ 650 MeV/c

p/p ~ 4 % * Wedge-Shaped-Degrader (stopped K+ yield: 1.5 times

enriched)

1-5. Experimental principle

• Kaonic helium4 formation from stopped K-

• Kaonic nuclear formation via nuclear Auger effect

• Neutron(proton) emission as a spectator

• Strong decay into mesonic or non-mesonic final states

Triple coincidence of

1. Incident kaon

2. Auger nucleon

3. Secondary charged particleMissing mass spectroscopy.

KN interaction-

))66.0/(exp()( 2rVrV TT DNK

))66.0/(exp()( 2rVrV TT 1CN,K

))66.0/(exp()( 2rVrV TT 2CN,K

0)( TT VrV

1TVD

1TV1C

1TV2C

-62 MeV

-285 MeV

-285 MeV

0TVD

0TV1C

0TV2C

-436 MeV-412 MeV

none

KpX 　　 Iwasaki et al. (1997)

fm)04.068.0()07.070.1(0 iaT

fm60.037.01 iaT

Martin (1981)

fm)12.025.049.0()03.015.078.0(pK- ia

p+K-n+K0-

(1405)

-++

++-

0+0

+0

5.30

-27

-94.9-103.0-104.4

-181.3

(MeV)

1-4. 4He(K-stopped, n/p) reactions -

population of the kbar - NNN states

4He(K-stopped, n) T=0,1 formation channel -> (K- - 3He)T=0, (K- - 3He)T=1,Tz=0

Appearance of a narrow peak was expected. 4He(K-

stopped, p) T=1 formation channel -> (K- - 3H)T=1,Tz=-

1

No narrow peaks were expected.

Research Topics (2 명 )

• I. Strangeness in Nuclear Physics

• 1. Hypernuclear Physics • 2. Kaonic Nucleus

• II. Extreme state • RI beam physics•

자세한 소개를 원하는 학생은

언제든지

연구실 (27-109 호 ) 이나

실험실 (25-108 호 ) 을

방문하여 주십시오 .

In-medium Hadrons: Brown-Rho scaling (1991)

• Partial restoration of chiral symmetry• ms*(ρ)/ms = mN* (ρ) /mN = mr* (ρ)/mr• = fπ* (ρ) /fπ = [<qq> (ρ) /<qq>0]1/2 quark

condensate• How to measure m*(ρ) in a well-define medium

density ρ ?• Invariant-mass spectroscopy applied to

decaying X in medium ?! Quasi-invariant mass • - disturbances caused by collisions• New method: bound-state spectroscopy of X,• if narrow• X = π-Deeply bound pionic states• X = K-Strongly bound kaonic states

Akaishi-TY, PRC (2002)KN interactionderived fromcoupled-channel calculationsBased on empirical dataI=0: Extremely attractive

SINC: Check of validity

Check for mass number dependence Check for energy dependence

Np/Nn for 12Λ C w/ SINC

Note that updated neutron yield reduced again from these figures

ProtonProton sum yield

Neutron

Neutron sum yieldNow 0.7 @40MeV

1. Nuclear Reaction Code

SINC (INC code of SNU)

II. Nuclear Application R/D 분야 [ 1 명 ]

- Nuclear Reactions- Radiations of Various kinds and

Energies- Detection Tech. - Isotopes

--> Powerful multi-dimensional

Technology sources. --> First, we are going to to

Monte Carlo simulation on the

Radiation therapy

--> Radio-endoscope

1. Nuclear Reaction Code

SINC (INC code of SNU)

2. Radio-Endoscope ( 방사내시경 )

Gamma knife

Cyber knife

2. Radio-Endoscope ( 방사내시경 )

3 . 1 2 Λ C d e c a y - Γ n / Γ p r a t i o

R a m o s e t a l .

P r o t o n e n e r g y s p e c t r u m1/ for pn

Ob

serv

ed p

roto

n/1

0MeV

includednot is

NNNNN

20.009.017.1/ pn

s t a t i s t i c a l branch 0error

O . H a s h i m o t o e t a l .Ａ ｃ ｃ ｅ ｐ ｔ ｅ ｄ ( Ｐ Ｒ Ｌ )

22.010.096.0/ pn

1 N

1 N & 2 ND e t e c t o r

s i m u l a t i o n

T3

T2

T1

T0Target

K

Neutron

E369 Decay counter

Experimental target: 12C, 51V and 89YObservable:

LifetimeBranching ratios of charged particleProton and neutron energy spectra

n / γseparation by TOF method

n

σ ～200ps

γ

σ =2/3/5/8MeV at En=30/50/70/100MeV

3. Neutron measurement：E369

Neutron from 12Λ C,89

Λ Y NMWD

2 MeVee thresholdS/N ～ 15S ～ 189 counts

10 MeVee thresholdS/N ～ 1S ～ 26 counts

1/β -plot of neutral particles

1/β

12Λ C

89Λ Y

BNL Szymanski PRC43, 849(1991)

Threshold from 2MeVee cut

* Acceptance corrected *ε (En) corrected

Typical threshold for decay proton analysis

89Λ Y

Nn

/ Nn

m/1

0MeV

Γ m/Γ total～0

Neutron Energy (MeV)

12Λ C

Γ m/Γ total=0.28

Charged particle：・ TOF (T2→T3)・ tracking（ PDC）Neutral particle：・ TOF (target→NT)・ T2/T3 VETO

p

n

π

K

Setup (E462) ( KEK -PS K6 beamline & SKS)

Decay arm

N: 20cm×100cm×5cmT3: 10cm×100cm×2cmT2: 4cm×16cm×0.6cm

Solid angle: 26%9(T)+9(B)+8(S)%

Comparison of Angular Correlation of He and C

We notice that

1. R(np) enhancement in C over He.

FSI?

2. R(nn) enhancement over R(np) both in He and C

2N?

where R=Nbb/Nnbb

5ΛHe 12

ΛCnp pair

nn pair

np pair

nn pairnbb

Preliminary Results