2. 1 Zhangbu Xu （许长补） Search for Exotic Particles

3. 2 Strange Quark Matter  Low Charge-to-Mass Ratio |Z|/m<<1 (A=2 10 57 )  Hybrid states (H-d,  q -p) Witten, PRD 30(1984)272 Jaffe, PRL 38(1977)617E n, e, 

4. 3 Why Strange Quark Matter?  QCD Allowed New States  QCD Lab. (quarks&gluons)  Future Energy Source  Star Fates

5. 4 Strangelet Production  High energy density and/or baryon density  Production models Coalescence production Distillation of QGP Thermal production Greiner, et al, PRD 38(1988) 2797 Baltz, et al, PLB 325(1994) 7 P. Braun-Munzinger, et al, JPG 21(1995)L17

6. 5 http://www.th.physik.unifrankfurt.de /~stoecker/vortrag2/strangelet.html

7. 6 Strangelets (Small Lumps of Strange Quark Matter) Roughly equal numbers of u,d,s quarks in a single ‘bag’ of cold hadronic matter. SQM is less stable for lower baryon number (due curvature energy) for A<~1000 There are likely significant shell effects at low A. E/A (MeV) A Bag model results with varying m s values

8. 7 Sources of Stable Strangelets? Relics of Early Universe? (Dark Matter?)  Skylab, TREK: Satellite based Lexan. No events Z>100  ARIEL-6, HEAO-3. scintillators, cerenkov counters. No events Z>100  HECRO-81:Saito et al. scintillator, Cerenkov in balloon at 9gm/cm2. 2 Z=14 undercutoff events. A of 110(370) to be above cutoff(mean rigidity). E/A~.45 GeV  ET event Ichimura et. Al. emulstion chamber in balloon at few g/cm2 but trajectory would have taken it through ~200gm/cm2. Z~30. A measured at 460  Price monopole. Lexan and emulsions in balloon experiment. Constant ionization through Lexan and low number of delta rays for normal nucleus. One interperetation is Z=45 and mass of 1000-10000  Centauro (original)  SLIM: mountaintop Lexan CR detector  Fossil Tracks (in meteorites)  Mica: look for tracks traversing 10**7 g/cm2  Mountaintop. Look for tracks traversing ~600 g/cm2  Sea Level:tracks traversing 10**3 g/cm2  Underground: tracks traversing 10**4 g/cm2  Centauro:1000Tev shower at 500g/cm2, mass~200. Small em component (decay into strange baryons?) and very penetrating (SQM glob which isn’t destroyed by nuclear interactions?)  Ke Han: PRL 103 (2009) 092302 Lunar Soil

9. 8 E. Finch-SQM 2006 How to find stable strangelets?  “Best” way: measure cosmic ray spectrum with high precision spectrometer…AMS aboard the ISS

10. 9 Limits on Strangelet Production Also negatively charged, neutral

11. 10 Zhangbu Xu （许长补） (for the STAR Collaboration) Observation of and @ RHIC ( 观测反超氚核） Introduction & Motivation Evidence for first antihypernucleus – and signal (for discovery) – Mass and Lifetime measurements Production rate and ratios – Yields as a measure of correlation – A case for RHIC energy scan Conclusions and Outlook

12. 11 The first hypernucleus was discovered by Danysz and Pniewski in 1952. It was formed in a cosmic ray interaction in a balloon-flown emulsion plate. M. Danysz and J. Pniewski, Phil. Mag. 44 (1953) 348 M. Danysz and J. Pniewski, Phil. Mag. 44 (1953) 348 What are hypernuclei （超核） ? Hypernuclei of lowest A Y-N interaction: a good window to understand the baryon potential Binding energy and lifetime are very sensitive to Y-N interactions Hypertriton:  B=130±50 KeV; r~10fm Production rate via coalescence at RHIC depends on overlapping wave functions of n+p+   in final state Important first step for searching for other exotic hypernuclei (double-  ) No one has ever observed any antihypernucleus Nucleus which contains at least one hyperon in addition to nucleons.

13. 12 from Hypernuclei to Neutron Stars hypernuclei  -B Interaction Neutron Stars S=-1 S=-2 S=-0 Several possible configurations of Neutron Stars – Kaon condensate, hyperons, strange quark matter Single and double hypernuclei in the laboratory: – study the strange sector of the baryon-baryon interaction – provide info on EOS of neutron stars J.M. Lattimer and M. Prakash, "The Physics of Neutron Stars", Science 304, 536 (2004) J. Schaffner and I. Mishustin, Phys. Rev. C 53 (1996): Hyperon-rich matter in neutron stars Saito, HYP06

14. 13 PANDA at FAIR 2012~ Anti-proton beam Double  -hypernuclei  -ray spectroscopy MAMI C 2007~ Electro-production Single  -hypernuclei  -wavefunction JLab 2000~ Electro-production Single  -hypernuclei  -wavefunction FINUDA at DA  NE e + e - collider Stopped-K - reaction Single  -hypernuclei  -ray spectroscopy (2012~) J-PARC 2009~ Intense K - beam Single and double  -hypernuclei  -ray spectroscopy  HypHI at GSI/FAIR Heavy ion beams Single  -hypernuclei at extreme isospins Magnetic moments SPHERE at JINR Heavy ion beams Single  -hypernuclei Basic map from Saito, HYP06 Current hypernucleus experiments

15. 14 Can we observe hypernuclei at RHIC? Z.Xu, nucl-ex/9909012  In high energy heavy-ion collisions: – nucleus production by coalescence, characterized by penalty factor. – AGS data [1] indicated that hypernucleus production will be further suppressed. – What’s the case at RHIC?  Low energy and cosmic ray experiments (wikipedia): hypernucleus production via –  or K capture by nuclei – the direct strangeness exchange reaction hypernuclei observed – energetic but delayed decay, – measure momentum of the K and  mesons [1] AGS-E864, Phys. Rev. C70,024902 (2004) | 聚并

16. 15 A candidate event at STAR Run4 (2004) 200 GeV Au+Au collision

17. 16 3  H mesonic decay, m=2.991 GeV, B.R. 0.25; Data-set used, Au+Au 200 GeV ~67M Run7 MB, ~23M Run4 central, ~22M Run4 MB, |VZ| < 30cm Track quality cuts, global track nFitsPts > 25, nFitsPts/Max > 0.52 nHitsdEdx > 15 P t > 0.20, |eta| < 1.0 Pion n-sigma (-2.0, 2.0) Data-set and track selection Secondary vertex finding technique DCA of v0 to PV < 1.2 cm DCA of p to PV > 0.8 cm DCA of p to 3 He < 1.0 cm Decay length > 2.4 cm

18. 17 3 He & anti- 3 He selection Select pure 3 He sample: -0.2 2 GeV 3 He: 2931(MB07) + 2008(central04) + 871(MB04) = 5810 Anti- 3 He: 1105(MB07) + 735(central04) + 328(MB04) = 2168

19. 18 signal from the data  background shape determined from rotated background analysis;  Signal observed from the data (bin-by-bin counting): 157 ± 30 ;  Projection on antihypertriton yields: constraint on antihypertriton yields without direct observation STAR Preliminary

20. 19  Signal observed from the data (bin-by-bin counting): 70±17; Mass: 2.991±0.001 GeV; Width (fixed): 0.0025 GeV; signal from the data STAR Preliminary

21. 20 Combine hypertriton and antihypertriton signal: 225 ± 35 Combined signals STAR Preliminary This provides a >6  signal for discovery

22. 21 Lifetime  Our data:  Consistency check on  lifetime yields  (  )=267±5 ps [PDG: 263 ps]. STAR Preliminary

23. 22 Comparison to world data  Lifetime related to binding energy  Theory input: the  is lightly bound in the hypertriton [1] R. H. Dalitz, Nuclear Interactions of the Hyperons (Oxford Uni. Press, London, 1965). [2] R.H. Dalitz and G. Rajasekharan, Phys. Letts. 1, 58 (1962). [3] H. Kamada, W. Glockle at al., Phys. Rev. C 57, 1595(1998). STAR Preliminary

24. 23 Measured invariant yields and ratios In a coalescence picture: 0.45 ~ (0.77) 3 STAR Preliminary

25. 24 Antinuclei in nature (new physics) Dark Matter, Black Hole  antinucleus production via coalescence To appreciate just how rare nature produces antimatter (strange antimatter) AMS antiHelium/Helium sensitivity: 10 -9 RHIC: an antimatter machine Seeing a mere antiproton or antielectron does not mean much– after all, these particles are byproducts of high-energy particle collisions. However, complex nuclei like anti-helium or anti-carbon are almost never created in collisions.

26. 25 What can we do with antimatter Weapon? Rocket propulsion 《天使与魔鬼》

27. 26 hypernuclei and antimatter from correlations in the Vacuum Real 3-D periodic table Pull  from vacuum (Dirac Sea)

28. 27 Matter and antimatter are not created equal RHIC SPS Nucl-ex/0610035 But we are getting there ! AGS STAR PRL 87(2003) NA52 (AGS,Cosmic) 物质和反物质造而不平等

29. 28 Flavors (u,d, s) are not created equal except in possible QGP J. Rafelski and B. Muller, Phys.Rev.Lett.48:1066,1982 STAR whitepaper, NPA757(2005)

30. 29 Yields as a measure of correlation A=2  Baryon density A=3  ; S. Haussler, H. Stoecker, M. Bleicher, PRC73 UrQMD Caution: measurements related to local (strangeness baryon)-baryon correlation Simulations of (all strangeness)—(all baryon) correlation

31. 30 ( 3 He, t, 3  H)  (u, d, s) A=3, a simple and perfect system 9 valence quarks, ( 3 He, t, 3  H)  (u, d, s)+4u+4d Ratio measures Lambda-nucleon correlation RHIC: Lambda-nucleon similar phase space AGS: systematically lower than RHIC  Strangeness phase-space equilibrium 3 He/t measures charge-baryon correlation STAR Preliminary uud udd udu uud udd uud udd uds 3 Het 3H 3H

32. 31  Primordial  -B correlation STAR Preliminary Caution: measurements related to local (strangeness baryon)-baryon Lattice Simulations of (all strangeness)—(all baryon) correlation correlation at zero chemical potential A.Majumder and B. Muller, Phys. Rev. C 74 (2006) 054901

33. 32 Energy scan to establish the trend Hypertriton only STAR: DAQ1000+TOF Beam energy200(30—200) GeV~17 (10—30)GeV~5 (5-10) GeV Minbias events# (5  ) 300M~10—100M~1—10M Penalty factor144836848 3 He invariant yields1.6x10 -6 2x10 -4 0.01 3  H/ 3 He assumed1.00.30.05

34. 33 Hypernuclei sensitive to phase transition AMPT Simulation of nucleon coalescence (with or w/o string melting): a) C BS is not sensitive to phase transition b) Strangeness population from hypertriton sensitive to phase transition

35. 34 / 3 He is 0.82 ± 0.16. No extra penalty factor observed for hypertritons at RHIC. Strangeness phase space equilibrium  The / 3 He ratio is determined to be 0.89 ± 0.28, and  The lifetime is measured to be  Consistency check has been done on analysis; significance is ~5   has been observed for 1 st time; significance ~4 . Conclusions  The / ratio is measured as 0.49±0.18, and 3 He / 3 He is 0.45±0.02, favoring the coalescence picture.

36. 35 Outlook  Lifetime: – data samples with larger statistics  Production rate: – Strangeness and baryon correlation Need specific model calculation for this quantity – Establish trend from AGS—SPS—RHIC—LHC   3 H  d+p+  channel measurement: d and dbar via ToF.  Search for other hypernucleus: 4  H, double  -hypernucleus.  Search for anti-   RHIC: best antimatter machine

37. 36 What can CSR contribute?  CSR 12 C, 40 Ca ( GeV), At the threshold of K,  production  Perfect for hypernucleus production Hypertriton lifetime, binding energy, absorption  Strangeness phase space population at CSR energies Exotic hypernuclei (proton/neutron rich, Sigma)  外靶实验装置适合超核重建 : Dipole, tracking, TOF and neutron wall  To do list: Tracking before Dipole (GEM, Silicon, MPWC) Model Simulations Detector Simulations Electronics and DAQ

38. 37 Vision from the past The extension of the periodic system into the sectors of hypermatter (strangeness) and antimatter is of general and astrophysical importance. … The ideas proposed here, the verification of which will need the commitment for 2-4 decades of research, could be such a vision with considerable attraction for the best young physicists… I can already see the enthusiasm in the eyes of young scientists, when I unfold these ideas to them — similarly as it was 30 years ago,… ---- Walter Greiner (2001)

39. 38 PANDA at FAIR 2012~ Anti-proton beam Double  -hypernuclei  -ray spectroscopy MAMI C 2007~ Electro-production Single  -hypernuclei  -wavefunction JLab 2000~ Electro-production Single  -hypernuclei  -wavefunction FINUDA at DA  NE e + e - collider Stopped-K - reaction Single  -hypernuclei  -ray spectroscopy (2012~) J-PARC 2009~ Intense K - beam Single and double  -hypernuclei  -ray spectroscopy  HypHI at GSI/FAIR Heavy ion beams Single  -hypernuclei at extreme isospins Magnetic moments SPHERE at JINR Heavy ion beams Single  -hypernuclei Basic map from Saito, HYP06 International Hyper-nuclear network BNL Heavy ion beams Anti-hypernuclei Single  -hypernuclei Double  -hypernuclei CSR at IMP?