Electron/Hadron Physics in Korea (in a personal view) 방 형 찬 고에너지협의회 회 서울대 상산 205 Oct. 06, 2005 I. Overview/Electro-Hadron Physics II. Main Physics in Electro-Hadron Physic III. Physics at JPARC IV. 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 g 1 (x) and g 2 (x) Experimental verification of various QCD sum rules Comparison of integrals with theoretical calculations  Role of Korean Physicists - 한국인 책임연구원 JLAB 실험 E ;Neutron spin structure functions at higher Q2 E ;Spin structure functions of the proton E05-1XX (approved Aug. 2005); L/T separation for quasi-elastic scattering PR ; Measurement of the neutron d2 matrix element

Two Examples of Sum Rules Significant improvement of errors for Bjorken Sum at low Q 2 First measurement of Burkhardt-Cottingham sum rule on the neutron at low Q 2 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 Y nn nbb (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=N bb /N nbb 15 counts 8 counts

K - potentials and bound states Y. Akaishi and TY, PRC (2002) Narrowing mechanism: E K <  threshold TY and Y. Akaishi, PLB (2002)

proton data neutron data Mass spectra nucl-ex/ χ2/DOF = 28.52/31 Gaussian center: MeV/c2 Gaussian sigma: 7.3 MeV/c2 Statistical 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 Baryons New Searches J-PARC Outlook nK + Penta-Quark Search at Spring8/LEPS

Exotic Baryons New Searches J-PARC Outlook  p/n n/p  K + /K 0  MMd(γ,K － p) GeV/c 2 Quasi-free  and non- resonant KKp   Bump structure  d   +  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 높이 기 위해 노력한다. 이를 위해 좋은 연구 Proposal 을 제출하고 성 공적으로 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 이 러한 연구가 순조롭게 진행될 수 있도록 하는 방안을 학계 차원 에서 찾을 필요가 있다.

Extra Slides

Proposals at JLab E –Neutron spin structure functions at higher Q 2 E –Spin structure functions of the proton E05-1XX (approved Aug. 2005) –L/T separation for quasi-elastic scattering PR –Measurement of the neutron d 2 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 azimuthal distribution of the lepton pair Access another transversity of the nucleon, h 1 ⊥ h 1 ⊥ describes transverse quark distributions in unpolarized hadrons  DIS - The Bottom Line: DIS cannot measure transversity - Transversity measurement involves spin flip - DIS conserves helicity of the constituents

A n from pN scattering JPARC LOI03 will do the similar experiment at JPARC with polarized proton target With the polarized neutron ( 3 He) target under development in Korea, we can measure A n 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) Γ m Γ nm Γ π- ( Λ  pπ - ) Γ πo ( 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 : Γ n /Γ p ( ≡ 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. Γ nm Γ n /Γ p BNL 5 Λ He0.41± ± Λ C1,14± ±1.12/0.81 KEK ’ Λ C0.89± ±0.91/1.59 Status of Γ n /Γ p long standig puzzle Γ n /Γ p exp >> Γ n /Γ p th(OPE) ~ 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/E Recent Development of Γ n /Γ p theory : 0.3 ~ 0.7

Singles spectrum in NMWD

p n π K Setup E462/E508 (KEK-PS K6 beamline & SKS) N: 20cm×100cm×5cm T3: 10cm×100cm×2cm T2: 4cm×16cm×0.6cm Solid angle: 26% 9(T)+9(B)+8(S)% π K

Energy spectrum in NMWD 1.Sharp peak in Y np (He) at Q value.  FSI negligible in He. 1.  Broad spec in Y nn (He) FSI? No. π - absorption or 2N? π - can not make it broad.  Must be 2N effect!! 3. Y np (C); FSI is significant. 4. Y nn (C); Even further degraded.  Again must be 2N. E sum = E n + E p E sum = E n1 + E n2 QQ Q Q

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 Y nn nbb (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=N bb /N nbb 15 counts 8 counts

Mijung result for 2N

Summary on Hypernuclear Physics 1.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~15cm 3. Prefered full open 2π angle. 4. Open target area in Z ;  1 m 5. 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 N π+ of E508, 1. N np nbb =8, N nn nbb =15, N NNN = 7(3) 2. ε p ~ 5 ε p0  8 ε p0 3. ε n ~ (5/3) ε n0  (7/3) ε n0  N np new = 5 (5/3) N np = 8.3 N np = 65  145  N nn new = (5/3) 2 N nn = 2.8 N nn = 42 counts  84  N NNN new = 5 (5/3) 2 N NNN = 14 x 7(3) ~ 100 (40) triple coin.  300(120)  Γ2N with 15% error, not with % error!!

Deeply Bound K-Nuclei Current LOI on Dense K-nuclear states;  (K-,N) reaction  (K-,π-) and (π+,K+) reaction K-K- K Atomic states Nuclear state One LOI, but very inclusive one.

E 1s  1s  1s } E 2p width  1s  [eV] shift  1s [eV] Davies et al, 1979 Izycki et al, 1980 Bird et al, 1983 repulsiveattractive KpX (KEK) M. Iwasaki et al, 1997  = ± 63 ± 11 eV  = 407 ± 208 ± 100 eV DEAR Kaonic hydrogen puzzle spd f Stark effect a T=0 =-1.7 fm a T=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 boun d state of K - p Atomic ground state is 2s bound state. --->> Akaishi-Yamazaki constructed a phenomenological KN interaction combining 1. Kp scattering length 2. K atom data 3. Λ(1405) as Kp bound state

K - potentials and bound states Y. Akaishi and TY, PRC (2002) Narrowing mechanism: E K <  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)ρ 0 - chiral symmetry restoration? - deconfined quark-gluon phase?

Diagram Kaon Bound System

ppK - bound system - kaonic “hydrogen molecule”

2. Experiment

Proton PID on NC

4 He(K - stopped,p) spectra Semi-inclusive momentum spectrum A significant peak structure Exists 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 S 0

proton data neutron data Mass spectra nucl-ex/ χ2/DOF = 28.52/31 Gaussian center: MeV/c2 Gaussian sigma: 7.3 MeV/c2 Statistical significance: S/ΔS=120/32= 3.7 σ

Summary of E471 results See analysis detail on

K - 3 He atom ~  threshold theory (isospin singlet) E What is the situation ？ theory (isospin triplet) pn particle(other) observed (isospin triplet) ~ 200 MeV (isospin singlet) (theory) (experiment) Binding energy

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 LOI Dense 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- K Atomic states Nuclear state

E 1s  1s  1s } E 2p width  1s  [eV] shift  1s [eV] Davies et al, 1979 Izycki et al, 1980 Bird et al, 1983 repulsiveattractive Kaonic hydrogen puzzle spd f Stark effect a T=0 =-1.7 fm a T=1 = 0.37 fm Status of the study of Deeply bound K - nucleus

III. Proposal for K1.1 GeV/c 1.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 rad = 5.5 o , 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 ΔxΔx

E307 E369 E462/E508

Γ tot (=1/τ) Γ m Γ nm Γ π- ( Λ  pπ - ) Γ πo ( 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. Γ nm Γ n /Γ p BNL 5 Λ He0.41± ± Λ C1,14± ±1.12/0.81 KEK ’ Λ C0.89± ±0.91/1.59 Status of Γ n /Γ p long standig puzzle Γ n /Γ p exp >> Γ n /Γ p th(OPE) ~ 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/E Recent Development of Γ n /Γ p theory : 0.3 ~ 0.7

N p /decay where 2N ; ΛNN  NNN. Proton Energy spectrum & Final State Interaction INC N p /nm ~0.4 Ramos et al. Λ+n  n+n Λ+p  n+p Sato et al., PRC submitted INC

Nn=0.69 Neutron Spectrum Efficiency Np = n yield is directly compared with that of p Simple number counting gives PRC 68 (03) Λ+n  n+n Λ+p  n+p

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=N bb /N nbb 5 Λ He 12 Λ C np pair nn pair np pair nn pair nbb Preliminary Results

5 Λ He : 0.61±0.081±0.082 (E462) 12 Λ C : 0.58±0.06±0.08 (E508) : ( 0.45~0.51)± 0.15 (E307/E369) Γ n /Γ p Status  n /  p Exp. OPE OME, DQ model 5 Λ He : 0.45 ±0.11 ±0.03 ± (E462) 12 Λ C : 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 decay widths and decay asymmetry parameters of Λ hypernuclei resolving the long standing puzzles on Гn/Гp and α NM. 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 5 Λ He (E462)  Γ n /Γ p ( 5 Λ He) = 0.61 ± ± Λ C (E508)  Γ n /Γ p ( 12 Λ C) = 0.58 ± 0.06 ± Λ He (E462)  Γ n /Γ p ( 5 Λ He) = 0.61 ± ± Λ C (E508)  Γ n /Γ p ( 12 Λ C) = 0.58 ± 0.06 ± Correction for Cross over recoil effects Similiarly for the coincidence yields of 5 Λ He and 12 Λ C (E462/E508), where β’ is reduced β due to the back-to-back selection. 5 Λ He (E462)  Γ n /Γ p ( 5 Λ He) = 0.43 ± 0.12 ± Λ C (E508)  Γ n /Γ p ( 12 Λ C) = 0.50 ± 0.13 ± Λ He (E462)  Γ n /Γ p ( 5 Λ He) = 0.43 ± 0.12 ± Λ C (E508)  Γ n /Γ p ( 12 Λ C) = 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) 52 T. 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* = f p *(0.6r 0 ) 2 /f p 2 = */ 0 ~ 0.65 at r=r 0 The 1st clear support for the whole scenario: quantitative agreement with theoretical predictions isoisosoisoisoso Isovector s-wave  N scattering length

DA  NE K  X-ray 1S 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…

Classification of the momentum spectrum 3- neutron coincidence 1. Strange tribaryon or Two-nucleon absorption -> on both 2. Hypernuclear decay -> only on n-anticoincidence 3. Instrumental bias -> on both ….. Hyper nuclear decay is NOT likely.

4-5. Summary of the analysis a): event topology of hypernuclear cascade b),c): indication of analysis 1,2

2-2. kaon beam li ne Secondary K - beam extracted throu gh KEK-PS K5 * 2TP(Tera Proton)/spill(1.6 sec duration with 4 sec cycle) * 6cm thick Pt production target * p K ~ 650 MeV/c  p/p ~ 4 % * Wedge-Shaped-Degrader (stopped K + yield: 1.5 times enrich ed)

4-7. Systematic error of the mass and the natural wi dth Systematic error: Source1: The deviation of Gaussian center due to the variation of BG functional shape ->  M 1 = 0.0 ~ -1.0 MeV/c 2 Source2: Uncertainty of TOF origin,  = ~ >  M 2 = +3.8 ~ -1.0 MeV/c >  M S 0 =  M 1 +  M 2 = +3.8 ~ -2.0 MeV/c 2 Natural width: Missing mass resolution is not clearly known, and the lower limit of the fitted Gaussian sigma is below the upper limit of the estimate d resolution-> Only upper limit of the width has been estimated. Source1: Statistical error of the P3-BG fitting Source2: Systematic error of Gaussian  due to the variation of BG functional shape. Source3: Missing mass resolution lower limit 6.4 MeV/c 2 By simple de-convolution of the resolution … > 21.6 MeV/c 2 (by 95 % C.L.)

1-5. Experimental principle Kaonic helium4 formatio n from stopped K - Kaonic nuclear formatio n via nuclear Auger effe ct Neutron(proton) emissio n as a spectator Strong decay into meso nic or non-mesonic final states Triple coincidence of 1. Incident kaon 2. Auger nucleon 3. Secondary charged particle Missing mass spectroscopy.

KN interaction MeV -285 MeV -436 MeV -412 MeV none KpX Iwasaki et al. (1997) Martin (1981) p+K - n+K 0 -  (1405) -++-++ ++-++- 0+00+0 +0+ (MeV)

He(K - stopped, n/p) reactions - populati on of the kbar - NNN states 4 He(K - stopped, n) T=0,1 formation channel -> (K He) T=0, (K He) T=1,Tz= 0 Appearance of a narrow peak was expected. 4 He(K - stopped, p) T=1 formation channel -> (K H) 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 ( 호 ) 이나 실험실 ( 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 = [ (ρ) / 0]1/2 quark conde nsate How to measure m*(ρ) in a well-define medium densi ty 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 interaction derived from coupled-channel calculations Based on empirical data I=0: Extremely attractive

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 )

Charged particle ： ・ TOF (T2 → T3) ・ tracking （ PDC ） Neutral particle ： ・ TOF (target → NT) ・ T2/T3 VETO p n π K Setup ( E462 ) (KEK-PS K6beamline& SKS) Decay arm N: 20cm × 100cm × 5cm T3: 10cm × 100cm × 2cm T2: 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=N bb /N nbb 5 Λ He 12 Λ C np pair nn pair np pair nn pair nbb Preliminary Results