Eunhee Kim 1,2 for HypHI collaboration 2 1 Seoul National University, 2 GSI, Germany

1. Hypernuclear Spectroscopy with Heavy Ion Collisions (HypHI)The HypHI Phase 0 experiment at GSI Eunhee Kim1,2 for HypHI collaboration2 1 Seoul National University, 2 GSI, Germany ND2010 29April2010

2. L0 S- d s X- d u s s d d s s s s W- Hypernuclei: Laboratory for baryon-baryon interaction with hyperon • In order to understand baryon-baryon interaction under flavor SU(3), we need to investigate interactions involving nucleons and hyperons. • Information of NN(nucleon-nucleon) interactions mainly obtained from NN scattering experiments. • Lack of information on YN(hyperon-nucleon) and YY(hyperon-hyperon) interactions • Difficulties to study YN and YY interactions by reaction experiments • No hyperon target available due to short lifetime (tY ~ 10-10 s) • Impractical to produce hyperon beams with proper energy • Hypernuclei are bound nuclear system with hyperon. • Hypernuclei can be used as a micro-laboratory to study YN and YY interactions.

3. Interests in hypernuclear physics • Structure and decay of hypernuclei at extreme isospin • Isospin dependence of YN and YY interactions • Hypernuclear magnetic moments • Property of hyperons in nuclear medium • Hypernuclear radii • Stability of hypernuclei Not possible with conventional hypernuclear spectroscopy via the (K-, -), (+, K+) and (e, e’K+) reactions. Reachable with heavy ion collisions. A project of hypernuclear spectroscopy with heavy ion induced reactions on a stable target nucleus, the HypHI project.

4. HypHI project • Hypernuclear production in the HypHI project • Energy threshold ~ 1.6 GeV for L production (NN → ΛKN) • - Stable heavy ion beams and RI beams with up to 2 AGeV can be achieved at GSI. • The produced hypernucleus has as large velocity as the projectile fragment. • Large Lorentz factor (g > 3) → longer lifetime → Hypernucleus in flight Projectile fragment Hot participant zone L Hypernucleus Projectile Target • A new doorway for hypernuclear spectroscopy

5. HypHI at GSI/FAIR: Concept of experiments • Produced hypernucleus close to projectile velocity • Large Lorents factor g > 3 • ct ~ 20 cm at 2 A GeV Mesonic weak decay : L→p-p Non-mesonic weak-decay : Lp → np Magnet Magnet n target L-Hypernucleus K Residues Time-of-Flight detectors Trackers N-detector K+ counter p, p

6. Present hypernuclear landscape Known hypernuclei

7. Hypernuclear landscape with HypHI Phase 1 (2009-2017) at GSI Proton rich hypernuclei Known hypernuclei 104 /week 103 /week

8. Hypernuclear landscape with HypHI Phase 1 (2009-2017) at GSI Proton rich hypernuclei Phase 1 (2009-2014) at GSI Proton rich hypernnuclei Phase 2 (2017-) at R3B/FAIR Neutron rich hypernuclei Known hypernuclei 104 /week 103 /week

9. Hypernuclear landscape with HypHI Phase 1 (2009-2017) at GSI Proton rich hypernuclei Phase 1 (2009-2014) at GSI Proton rich hypernnuclei Phase 2 (2017-) at R3B/FAIR Neutron rich hypernuclei Known hypernuclei 104 /week 103 /week With hypernuclear separator Magnetic moments Phase 3 (201X-) at FAIR Hypernuclear separator

10. Hypernuclear landscape with HypHI Phase 1 (2009-2017) at GSI Proton rich hypernuclei Phase 1 (2009-2014) at GSI Proton rich hypernnuclei Phase 0 experiment in 2009: Demonstrate the feasibility of precise hypernuclear spectroscopy with heavy ion beams (6Li beam at 2 A GeV on 12C target) Phase 2 (2017-) at R3B/FAIR Neutron rich hypernuclei Known hypernuclei 104 /week 103 /week With hypernuclear separator Magnetic moments Known hypernuclei 104 /week 103 /week With hypernuclear separator Magnetic moments Phase 3 (201X-) at FAIR Hypernuclear separator

11. 3days in Aug. and 11days in Oct. 2009 Phase 0 experiment • To demonstrate the feasibility of the experimental methods of the HypHI project with 6Li beams at 2 A GeV by producing and identifying light hypernuclei ▶ Beam: 6Li at 2 A GeV with an intensity of 5 x106 /s ▶ Active Target : 12C with a thickness of 8 g/cm2 3LH → 3He + - 4LH → 4He + - 5LHe → 4He + p + - (0.75 T) ⊙ magnet direction

12. ALADiN magnet (0.75 T)

13. TOF start (Time-of-flight start) 5cm • For beam particles • Plastic fingers + small PMTs • : 1 MHz beam rate per finger • Time resolution: s ~ 200 ps

14. Scintillating fiber detectors TR0 TR1 TR2 13.2cm 24.5cm 3.8cm 7.6cm 3.8cm 11.3cm • 4352 fibers with a diameter of 0.83 mm • HAMAMATSU H7260KS MOD readout • X and Y tracking • : Position resolution: 0.46 mm (RMS) • For secondary vertex trigger • D. Nakajima, B. Özel-Tashenov et al., Nucl. Instr. and Meth. A 608 (2009) 287

15. Drift chambers Big DC Small DC 24cm 90cm 14cm 120cm • Wire plane: xx’vv’uu’ • Drift length: 2.5mm • Typical resolution(RMS): 0.30 mm • Gas: Ar 70% + CO2 30% • Insensitive in beam region • by wrapping seinse wires with teflon • Wire plane: XX’YY’U • Drift length: XY 4.5mm, U 9.0mm • Typical resolution(RMS): XY 0.30 mm, U 0.40mm • Gas: Ar 70% + CO2 30% • Insesitive in beam region • by connectiing sense and potential wires

16. ALADiN TOF wall 110cm 240cm • For p- • Plastic scintillators(96 bars)+ PMTs • Time resolution: s ~ 200 ps • Y position calculated by the difference between top and bottom TDCs.

17. Big TOF wall (TFW) 150cm 188.5cm • For p- • X and Y layers (18 bars + 14 bars) • Time resolution: s ~ 200 ps (RMS)

18. TOF + wall 1m 96cm hole : 7.5x6.5 cm2 • For a and proton • Plastic scintillators (16 bars × 2 layers) • with a hole for beam + PMTs • Time resolution: 357±3 ps (FWHM) • Energy resolution : 18 % (FWHM)

19. Problems and improvement of Phase 0 • Problems of Phase 0 experiment • Low efficiency of p- detection in ALADiN TOF wall • Many events for scattering particles from TOF+ holding structure • Improvement of setup in March • Movement of ALADiN TOF wall toward behind TOF+ wall • - Cross-check positively charged particles with high energy deposition • Movement of Big DC closer to Big TOF • - Avoid improper operation from much high multiplicity caused by 20Ne beam • - Remove the background events from TOF+ holding structure • Phase 0.5 experiment • Study of heavier hypernuclei • Beam: 20Ne at 2 A GeV with an intensity of 6 x105 /s • Target : 12C with a thickness of 8 g/cm2 • Performed in March 2010

20. 14 days in Mar. 2010 Phase 0.5 experiment • Beam: 20Ne at 2 A GeV with an intensity of 6 x105 /s • to study light and heavier hypernuclei together • Active Target : 12C with a thickness of 8 g/cm2 upstream downstream

21. Experimental performance • Phase 0 with 6Li beams • Multiplicity in TR1 • QDC in TOF+ • Phase 0.5 with 20Ne beams • Multiplicity in TR1 • QDC in TOF+ p p a C O Ne a Li

22. People working for HypHI Phase 0/0.5 • GSI Helmholtz-University Young Investigators Group VH-NG-239 • S. Bianchin • O. Borodina (Mainz Univ.) • V. Bozkurt (Nigde Univ.) • B.Göküzüm (Nigde Univ.) • E. Kim (Seoul Nat. Univ) • A. Le Fevre • D. Nakajima (Tokyo Univ.) • B. Özel • C. Rappold (Strasbourg Univ.) • T.R. Saito (Spokes person) • Mainz University • P. Achenbach, J. Pochodzalla • GSI HP2 and Mainz University • F. Maas, Y. Ma • GSI HP1 • W. Trautmann • GSI EE department • J. Hoffmann, K. Koch, N. Kurz,S. Minami, W. Ott, S. Voltz • GSI Detector Lab. • M. Träger, C. Schmidt • KEK • T. Takahashi, Y. Sekimoto • KVI • M. Kavatsyuk • Kyoto University • T. Nagae • Osaka University • S. Ajimura, A. Sakaguchi, K.Yoshida • Osaka Electro-Communication University • T. Fukuda, Y. Mizoi • Tohoku University • T. Koike, H.Tamura • Seoul National University • H.Bhang, K. Tanida, M.Kim, C.Yoon, S.Kim • Nigde University • S.Erturk, Z.S.Ketenci • Theoretical support • T. Gaitanos (Giessen), E. Hiyama (RIKEN), D. Lanskoy (Moscow), H. Lenske (Giessen), U. Mosel (Giessen)