1. Experimental Challenges for Hypernuclear Physics at Panda Patrick Achenbach U Mainz with contributions from the PANDA Hypernuclear groups Sept. 2o11

2. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz present limitations –only single Λ-hypernuclei close to valley of stability –only very few ΛΛ-hypernuclei events The hypernuclear landscape element = total charge (not number of protons) number of baryons N+Z+Y number of hyperons Y Example: 7 Λ Li ( 6 Li + Λ) increasing strangeness

3. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Physics with single hypernuclei: spectroscopy: nuclear structure and YN strong interaction, potential models … life-time and mesonic/non-mesonic weak decay: weak interaction … in-medium effects: change of Y-mass in nucleus, effects on magnetic moment... Physics with double hypernuclei: spectroscopy: test of YY strong interaction binding: – B  ( A  Z) = B  ( A  Z) - 2B  ( A-1  Z) accessible by emulsion experiments – contribution of exchange mesons in YN and YY interaction weak decay of double hypernuclei atomic  spectra (interplay of Coulomb and strong force) Hypernuclear physics increasing strangeness

4. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz [E. Hiyama, M. Kamimura, T.Motoba, T. Yamada and Y. Yamamoto, Phys. Rev. 66 (2002), 024007] many excited, particle stable states in double hypernuclei predicted level structure reflects levels of core nucleus Spectroscopy of ΛΛ-hypernuclei

5. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Excursion: strangeness in compact stars [P. B. Demorest et al., A two-solar-mass neutron star measured using Shapiro delay, Nature 467, (2010) 1081]  equation-of-state (EOS) with/without strangeness [J.R Stone, P.A.M. Guichon and A.W. Thomas]  experimental evidences of the 2M  neutron star does not exclude hyperons in the EoS

6. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz 1. dE( - )/dx  stop + capture 2. hyperatom + atomic decay 3. capture in nucleus ( - Z) 4. conversion:  - + p  ΛΛ 5. hypernuclei ( ΛΛ Z * or Λ Z*+ Λ Z‘ * ) strangeness production can only be tagged by the anti-hyperon or its decay products  forward detector for trigger and particle ID  PANDA at FAIR the hyperons may produce: single hypernuclei: Λ Z ( Σ Z) twin hypernuclei: Λ Z + Λ Z‘ doubly strange hypernuclei: - Z double hypernuclei: ΛΛ Z H particle in a nucleus(?): ΛΛ Formation of double hypernuclei from Xi particles

7. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz  3 GeV/c kaons   trigger p _ ➁ slowing down and capture of   in secondary target nucleus ➀ hyperon- antihyperon production at threshold  ➂  -spectroscopy of excited states     atoms: x-rays conversion:   p  Λ Λ ‏ Δ Q = 28 MeV conversion probability ~ 5-10% Production mechanism and detection strategy at PANDA     +28MeV     ④ decay pion spectroscopy [originally by J. Pochodzalla et al.]

8. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Instrumentation for hypernuclear physics at PANDA carbon wire primary target for Ξ production secondary target for hypernuclei formation Germanium detector array for hypernuclei spectroscopy the Panda detector for forward angle particle identification

9. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Open issues being studied by the Panda Hypernuclear Groups 1.design and fabrication of the primary target 2.design and development of the secondary target 3.design and operation of the HPGe  -array 4.electromechanical cooling of HPGe crystals 5.integration into the PANDA target spectrometer 6.simulation of the expected performance technicaltechnical physics

10. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Open issues being studied by the Panda Hypernuclear Groups 1.design and fabrication of the primary target 2.design and development of the secondary target 3.design and operation of the HPGe  -array 4.electromechanical cooling of HPGe crystals 5.integration into the PANDA target spectrometer 6.simulation of the expected performance

11. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Si ring outer =15 mm Si ring inner =11 mm Si ring thickness = 500 m diamond thickness = 3 m Si ring Wire Diamond [F. Iazzi, PANDA Meeting 06 Sept. 2011.] FESEM microscopy wire width: 99.9 m Prototype of the 12 C thin wire target

12. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Open issues being studied by the Panda Hypernuclear Groups 1.design and fabrication of the primary target 2.design and development of the secondary target 3.design and operation of the HPGe  -array 4.electromechanical cooling of HPGe crystals 5.integration into the PANDA target spectrometer 6.simulation of the expected performance

13. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Stopping of the Xi particles [PANDA Physics Performance Report, 2009.] target geometry adjusted to stopping time and lifetime of Ξ -

14. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz carbon beryllium boron anti-and annihilation products four separated sections: 20 layers of double sided silicon strip detectors (thickness 300 μm) in each block 20 layers of absorbers (thickness 1 mm) different for each block (Be, B and C) boron The secondary target design [PANDA Physics Performance Report, 2009.]

15. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Prototype developments for the secondary target  compact structure of detector and absorber: performance of silicon strip detector in direct contact with absorbers  space required for frontend electronics: minimization of additional material masses on detecting volume: ultra-thin Al-Polyimide readout cables [J.M. Heuser et al., HadronPhysics2/JRA-ULISI] [S. Bleser, U Mainz]

16. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Open issues being studied by the Panda Hypernuclear Groups 1.design and fabrication of the primary target 2.design and development of the secondary target 3.design and operation of the HPGe  -array 4.electromechanical cooling of HPGe crystals 5.integration into the PANDA target spectrometer 6.simulation of the expected performance

17. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz  simulation of different multiplicity of crystals  operation of double and triple cluster detector  high rate environment: radiation damages pile-up effects electromagnetic background  magnetic field environment: loss of resolution Towards a prototype of HPGe Cluster Array

18. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz [A. Sanchez Lorente et al., NIM A 573 (2007) 410.] Performance of HPGe detectors in magnetic fields  loss of resolution observed  correction by rise-time correlation possible

19. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Open issues being studied by the Panda Hypernuclear Groups 1.design and fabrication of the primary target 2.design and development of the secondary target 3.design and operation of the HPGe  -array 4.electromechanical cooling of HPGe crystals 5.integration into the PANDA target spectrometer 6.simulation of the expected performance

20. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Towards a prototype of HPGe Cluster Array [M. Steinen, U Mainz, I. Kojouharov, GSI] HPGe encapsulated crystal attached to electromechanical cooler X-Cooler Head, partially hidden inside the electronics chamber Electronics chamber Flexible cold finger and flexible cold finger tube. Allows full use of the space available for detectors. Detector Head fixing.

21. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Open issues being studied by the Panda Hypernuclear Groups 1.design and fabrication of the primary target 2.design and development of the secondary target 3.design and operation of the HPGe  -array 4.electromechanical cooling of HPGe crystals 5.integration into the PANDA target spectrometer 6.simulation of the expected performance

22. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz p [from D. Rodriguez]  dedicated beam pipe going from 150 mm to 20 mm diameter  backward end cap calorimeter and MVD will not be used  modular structure Target integration into the spectrometer

23. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz p [from D. Rodriguez]  lab < 45°:  -bar, K trigger and PID in PANDA spectrometer  lab = 45°-90°:  -capture and hypernuclei formation  lab >90°:  -detection with HPGe at backward angles integration of electromechanical coolers for HPGe [PANDA Technical Progress Report, 2005.] HPGe array integration into the spectrometer

24. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Open issues being studied by the Panda Hypernuclear Groups 1.design and fabrication of the primary target 2.design and development of the secondary target 3.design and operation of the HPGe  -array 4.electromechanical cooling of HPGe crystals 5.integration into the PANDA target spectrometer 6.simulation of the expected performance

25. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz What is the chance that individual excited, particle stable states of double hypernuclei are produced ? conversion width Ξ + p  ΛΛ about Г = 1MeV precise Ξ - binding energy not yet known (0.6 – 4 MeV) typical excitation energy ~ a few MeV/nucleon fragmentation of excited projectile remnants are well understood in that regime de-excitation of light nuclei via Fermi break-up process [A. Sanchez Lorente, A. Botvina et J.Pochodzalla, PLB 697 (2011) 222- 228)] example :   + 12 C  A+Z+H  Z  13  B * Statistical decay model for excited hypernuclei

26. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz Population of excited double hypernuclear states    + 12 C  13  B * : double hypernuclei : single hypernuclei : twin hypernuclei : ΛΛ  production of excited states of double hypernuclei is significant [A. Sanchez Lorente, A. Botvina et J.Pochodzalla, PLB 697 (2011) 222- 228]

27. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz    + 9 Be  10  Li * [A. Sanchez Lorente, A. Botvina et J.Pochodzalla, PLB 697 (2011) 222- 228] Population of excited double hypernuclear states

28. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz [PANDA Physics Performance Report, 2009. Simulations by A. Sanchez Lorente, U Mainz.] 9  Li g s 9  Be g s 9B9B p  eV p  eV Background suppression by decay pion correlation

29. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz PANDA will explore several targets: 9 Be, 10 B, 11 B, 12 C, 13 C B Li B C 9 Be target 12 C target 9  Li 8  He  sum of excited states  B Ξ = 0.5 MeV  sequential pionic decay prob. ≈ 0.45 - 0.03A  production probability · pionic decay probability 9  Li 11  Be  each target allows for the unique assignment of observable transitions by comparing the expected yields Hypernuclei charge Hypernuclei mass number Identification of individual isotopes

30. Experimental Challenges for Hypernuclear Physics at PANDA Sept. 2o11 P Achenbach, U Mainz  Hypersystems provide a link between nuclear physics and QCD to study basic properties of strongly interacting systems  antiproton collisions with nuclei are the ideal tool to produce exclusive Xi-antiXi pairs in nuclei at moderate momenta  many experimental challenges have to be overcome to realize such measurements  A statistical model predicts a large probability for the population of individual, excited states in double Λ hypernuclei  γ-spectroscopy of these double hypernuclei at PANDA is feasible SummarySummary