Hypernuclear Spectroscopy with Heavy Ion Collisions (HypHI) The HypHI Phase 0 experiment at GSI Eunhee Kim 1,2 for HypHI collaboration 2 1 Seoul National University, 2 GSI, Germany 1 ND April2010

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 (  Y ~ 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. s u d s d d s d s s s s    00 2

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 3 Not possible with conventional hypernuclear spectroscopy via the (K -,  - ), (  +, K + ) and (e, e’K + ) reactions. A project of hypernuclear spectroscopy with heavy ion induced reactions on a stable target nucleus, the HypHI project. Reachable with heavy ion collisions.

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

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

Present hypernuclear landscape 6 Known hypernuclei

7 Phase 1 ( ) at GSI Proton rich hypernuclei Known hypernuclei 10 4 /week 10 3 /week Hypernuclear landscape with HypHI

8 Phase 1 ( ) at GSI Proton rich hypernnuclei Hypernuclear landscape with HypHI Known hypernuclei 10 4 /week 10 3 /week Phase 1 ( ) at GSI Proton rich hypernuclei Phase 2 (2017-) at R3B/FAIR Neutron rich hypernuclei

9 Hypernuclear landscape with HypHI Phase 1 ( ) at GSI Proton rich hypernnuclei Phase 1 ( ) at GSI Proton rich hypernuclei Phase 3 (201X-) at FAIR Hypernuclear separator Known hypernuclei 10 4 /week 10 3 /week With hypernuclear separator Magnetic moments Phase 2 (2017-) at R3B/FAIR Neutron rich hypernuclei

10 Hypernuclear landscape with HypHI Known hypernuclei 10 4 /week 10 3 /week With hypernuclear separator Magnetic moments Phase 0 experiment in 2009: Demonstrate the feasibility of precise hypernuclear spectroscopy with heavy ion beams ( 6 Li beam at 2 A GeV on 12 C target) Known hypernuclei 10 4 /week 10 3 /week With hypernuclear separator Magnetic moments Phase 1 ( ) at GSI Proton rich hypernnuclei Phase 1 ( ) at GSI Proton rich hypernuclei Phase 3 (201X-) at FAIR Hypernuclear separator Phase 2 (2017-) at R3B/FAIR Neutron rich hypernuclei

Phase 0 experiment  To demonstrate the feasibility of the experimental methods of the HypHI project with 6 Li beams at 2 A GeV by producing and identifying light hypernuclei 3  H → 3 He +  - 4  H → 4 He +  - 5  He → 4 He + p +  - ▶ Beam: 6 Li at 2 A GeV with an intensity of 5 x10 6 /s ▶ Active Target : 12 C with a thickness of 8 g/cm 2 ⊙ magnet direction (0.75 T) 3days in Aug. and 11days in Oct

ALADiN magnet 12 (0.75 T)

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

Scintillating fiber detectors 14 ▶ 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 TR0TR1 TR2 3.8cm 24.5cm 11.3cm 13.2cm 7.6cm

Drift chambers 15 24cm 14cm 120cm 90cm Small DC Big DC ▶ Wire plane: xx’vv’uu’ ▶ Drift length: 2.5mm ▶ Typical resolution(RMS): 0.30 mm ▶ Gas: Ar 70% + CO 2 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% + CO 2 30% ▶ Insesitive in beam region by connectiing sense and potential wires

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

Big TOF wall (TFW) 17 ▶ For  - ▶ X and Y layers (18 bars + 14 bars) ▶ Time resolution:  ~ 200 ps (RMS) 150cm 188.5cm

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

Problems and improvement of Phase 0  Problems of Phase 0 experiment  Low efficiency of  - detection in ALADiN TOF wall  Many events for scattering particles from TOF+ holding structure 19 Phase 0.5 experiment ▶ Study of heavier hypernuclei ▶ Beam: 20 Ne at 2 A GeV with an intensity of 6 x10 5 /s ▶ Target : 12 C with a thickness of 8 g/cm 2 ▶ Performed in March 2010  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 20 Ne beam - Remove the background events from TOF+ holding structure

Phase 0.5 experiment 14 days in Mar ▶ Beam: 20 Ne at 2 A GeV with an intensity of 6 x10 5 /s to study light and heavier hypernuclei together ▶ Active Target : 12 C with a thickness of 8 g/cm 2 upstream downstream

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

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) 22