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Gang Chen, Huan Chen China University of Geosciences, Wuhan Collaborators

Production of light anti-nuclei, hyper-antinuclei, and their characteristics in high-energy nuclear collisions. Gang Chen, Huan Chen China University of Geosciences, Wuhan Collaborators Yu-Liang Yan, Ben-Hao Sa (CIAE, China) Dai-Mei zhou (CCNU, China).

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Gang Chen, Huan Chen China University of Geosciences, Wuhan Collaborators

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  1. Production of light anti-nuclei, hyper-antinuclei, and their characteristics in high-energy nuclear collisions Gang Chen, Huan Chen China University of Geosciences, Wuhan Collaborators Yu-Liang Yan, Ben-Hao Sa(CIAE, China) Dai-Mei zhou (CCNU, China) China-Norway Physics Workshop III,Wuhan, China, May 10, 2014.

  2. Outline • Found hypernuclei • Analysis Method • The Results • Summary

  3. Found hypernuclei

  4. S=-2 S=-1 S=-0 from Hypernuclei to Neutron Stars • hypernuclei L-B Interaction Neutron Stars Saito, HYP06 • Propose Several possible configurations of Neutron Stars • Kaon condensate, hyperons, strange quark matter 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

  5. Tracks in TPC • It is first fonud nuclear contain anti-strange quark; • The chart of nuclides is expand to the new anti-strange matter region. 5

  6. Measured invariant hypernucleiyields STAR, Science 328 (2010) 58 70±17 antihypertritons 157 ±30 hypertritons With About 89 million minimum-bias events and 22 million most central collisions events, from Au+Au collisions of √sNN=200 GeV (STAR) N AT U R E 4 7 3 (2 0 1 1)

  7. Found hypernuclei in the high energy collision exp. Production of antinuclei in pp collisions at 7 TeV with ALICE at the LHC Raw yield of anti-deuterons as a function transverse momentum N. Sharma ( ALICE) J.Phys.G 38 (2011);arXiv:1104.3311v2

  8. The discovery for hypernuclei in the high energy experiment have been widely fascinating the sights of nuclear physicists. So we try to proposed a dynamically constrained phase space coalescence model + PACIAE model and used to investigate the production of light nuclei (anti-nuclei) in high energy collisions .

  9. Analysis Method PACIAE model It is the parton and hadron cascade Model based on PYTHIA. 1. The string fragmentation in PYTHIA is switched-off temporarily and the diquarks (anti-diquarks) are broken randomly into quarks (antiquarks), so the parton initial state is obtained. 2. The parton rescattering is proceeded until partonic freez-out. 3. Then the hadronization is followed. 4. At last the hadronic rescattering is proceeded until hadronic freez-out. Ben-Hao Sa ,etal. Comput. Phys. Commun., 183, 333 (2012).

  10. Analysis Method Dynamically constrained phase space coalescence model In the theoretical studies, the yield of light nuclei (anti-nuclei) is usually calculated in two steps: (1)The nucleons and hyperons are calculated by the transport model. (2)The light nuclei (anti-nuclei) are calculated by the phase space coalescence model with Wigner function or by the statistical model . This coalescence model strongly relies upon the assumption of light nuclei (anti-nuclei) wave function used to construct the Wigner function . The statistical model strongly relies upon the equilibrium assumption and the fitted temperature and baryon chemical potential. We proposed a dynamically constrained phase space coalescence model to calculate the yield of light nuclei (anti-nuclei) after the transport model simulations. Ben-Hao Sa ,etal. Comput. Phys. Commun., 183, 333 (2012). Yu-Liang Yan, Gang Chen et al, Phys. Rev. C 85 024907 (2012).

  11. Dynamically constrained phase space coalescence model As the uncertainty principle one can only say particle lies somewhere within a six dimension quantum ``box" or “state" of volume of ΔqΔp However,we can estimate the yield of a single particle by Similarly for the yield of N particles cluster

  12. Dynamically constrained phase space coalescence model The yield of , for instance, is assumed to be Where, the constraints m0 stand for the rest mass of D0 stand for the Limiting the spatial position Δm refers to the allowed uncertainty.

  13. The Results in p+p coll. Yu-Liang Yan, Gang Chen et al, Phys. Rev. C 85 024907 (2012). The model parameters are fitted to the STAR data of strange particles as shown in the following table. TABLE I: Particle yield in NSD pp collisions at = 0.2 TeV. B. I. Abelev, et al., STAR , Phys. Rev. C 75 064901 (2007). Then they are used to calculate the yield of D, 3He, and , etc.,

  14. The Results of Hadron and light (anti)nuclei in p+p coll. Tab I: Hadron and light nuclei (anti-nuclei) yields in NSD p+p collisions at √s=7 and 14 TeV calculated by final hadronic state in the PACIAE and PYTHIA simulations. a Calculated with △m=0.0005 GeV. b Estimated from ALICE Data , J.Phys.G 38(2011) c Calculated with △m=0.005 GeV. predict the light (anti)nuclei yields in p+pcollisions at √s = 7 and 14 TeV.

  15. FIG. 1: Transverse momentum distributions of light anti-nuclei in the NSD pp collisions at = 7 and 14 TeV with PACIAE and PYTHIA model The green dots are ALICE data . The Results in p+p coll.

  16. The Results in p+p coll. The strong fluctuation, indicates that the 1.2 x108 events are not enough for the pT and y distribution of the particles. FIG. 2: Rapidity distributions of light anti-nuclei in the NSD pp collisions at =7 and 14 TeV with PACIAE and PYTHIA model

  17. The Results in Au+Au coll.at √sNN =200 GeV Chen Gang Yu-Liang Yan et al , PRC 86, 054910(2012) The model parameters are fitted to the STAR data of strange particles as shown in the following table and Fig 1. Then they are used to calculate the yield of D, 3He, and , etc., Tab 1 Hadron yields from Model in comparison with the STAR data STARa, PRL 98, 062301 (2007) A. Andronic et al., PLB 697, 203 (2011) Fig 1 Hadron yields from Model in comparison with the STAR data Obviously, the model results are very close to the data exp

  18. The Results in Au+Au coll.at =200 GeV Tab 2 Light (anti)nuclei yields of models in comparison with the STAR f Δm=0.0003 GeV. bΔm=0.00015 GeV. The yields in PACIAE model simulation are consistent with STAR data. egh The STAR, Science 328, 58 (2010); a L. Xue,Y. G. Ma et al.,PRC. 85 064912 (2012). c A. Andronic,et al., PLB 697(2011) Chen Gang et al , PRC 86, 054910(2012)

  19. The Results in Au+Au coll.at =200 GeV Fig 2 The comparison of particles ratios between data and model calculations. Chen Gang et al , PRC 86, 054910(2012) Tab 3 Light (anti)nuclei ratio in comparison with the STAR data The STAR yield ratios are good reproduced. Δm=0.0003 GeV for D, Δm=0.00015 GeV for , , ,

  20. The Results in Au+Au coll.at =200 GeV Fig 3 Transverse momentum distributions of light (anti)nuclei . Chen Gang et al , PRC 86, 054910(2012)

  21. Using PACIAE + the dynamically constrained phase space coalescence (DCPC) model to calculate the light nuclei (anti-nuclei) in high enengy collisions, it seams successful. • It turned out that PACIAE + DCPC model would be an effective method investigating the production of light (anti)nuclei in high energy collisions.

  22. The Centrality dependenceof light anti-nuclear produced in Au+Au coll. Chen Gang et al , PRC 88, 034908(2013) The yields in PACIAE model simulation are consistent with STAR data. FIG. 1. The integrated yield dN/dy of strange particle at midrapidity Au+Au collisions at 200 GeV as a function of centrality.

  23. The Centrality dependenceof light anti-nuclear produced in Au+Au coll. Chen Gang et al , PRC 88, 034908(2013) TAB I: Integrated yields dN/dy calculated by PACIAE+DCPC model . Δm=0.00035GeV for D, ; Δm=0.0002 GeV for , , , The yields in the DCPC model decrease (or increase) with the increase of centrality (or Npart); the yields of antinuclei are less than those of its corresponding nuclei; and the greater the mass is, the lower the yield.

  24. The Centrality dependenceof light anti-nuclear produced in Au+Au coll. Chen Gang et al , PRC 88, 034908(2013) The cumulative yield Yc is defined as STAR ,Science 328, 58 (2010) STAR ,arXiv:0909.0566 PHENIX , PRL. 94 , 122302 (2005). The yields in PACIAE + DCPC model simulation are consistent with Exp. data. FIG. 2: The cumulative yields YC for light (anti)nuclei and (anti) hypertriton， in midrapidity Au+Au collisions at √sNN = 200 GeV, plotted as a function of centrality.

  25. The Centrality dependenceof light anti-nuclear produced in Au+Au coll. Chen Gang et al , PRC 88, 034908(2013) Defined a normalized yield The curves are fitted by Theoretical and exp. results of yields in different centrality bins can be converted into the constant yield YMBfor direct comparison. FIG. 3: The normalized yield as a function of centrality bin， calculated by PACIAE + DCPC model in the midrapidity Au+Au collisions at √sNN= 200 GeV,

  26. The Centrality dependenceof light anti-nuclear produced in Au+Au coll. Chen Gang et al , PRC 88, 034908(2013) FIG. 4 Yield ratios of light (anti) nuclei and (anti) ypertriton in mid -rapidity Au+Au collisions at √sNN = 200 GeV, plotted as a unction of centrality. Their yield ratios also remain unchanged from central to peripheral coll.

  27. Scaling Properties of light antinuclei production in Au+Au coll. The differential invariant yield or light (anti)nuclei is described by the equation Fig 1 depicts a decreasing exponential trend of the invariant yields with the increased baryon number. Fig.1 Differential invariant yields of light (anti)nuclei as a function of baryon number, in Au+Au collisions at √sNN = 200 GeV Hecke, Sorge, Xu, PRL. 81, 5764 (1998). STAR , Nature 473,353 (2011); L. Xue,Y. G. Ma,PRC85, 064912 (2012)

  28. Scaling Properties of light antinuclei production in Au+Au coll. Chen Gang, arXiv:1401.6872, 2014 The yields in PACIAE + DCPC model simulation are consistent with Exp. data. Fit the curves to get the temperature at hadronic freeze-out: Fig.2: Atomic number dependence of the integrated yield dN/dy of light (anti)nuclei in different centrality Au+Au collisions at √sNN = 200 GeV 149 ± 3MeV for 0-5%, 142 ±4 MeV for MB, 125 ±6 MeV for 40-60%

  29. Scaling Properties of light antinuclei production in Au+Au coll. Chen Gang, arXiv:1401.6872, 2014 The yields of light (anti)nuclei and (anti)hypertriton decrease with the increase of the centrality. This distribution properties mainly depend on their mass number, i.e. the greater the mass number is, the faster the yield decreases. Fig 3: The integrated yield normalized to C=0-5%, as a function of centrality, in the midrapidity Au+Au collisions at √sNN =200 GeV.

  30. Scaling Properties of light antinuclei production in Au+Au coll. Defined a ratio of yield per Npart Fig 4: Relative invariant yields at midrapidity divided by Npart, as a function of Npart normalized to the peripheral collisions (40-60%).The results are calculated by PACIAE+DCPC model in Au+Au collisions at √sNN =200 GeV . We were surprised to find that the datum for all dfferent (anti)nuclei and (anti)hypertriton approache to the same straight line.

  31. Summary • The PACIAE+DCPC were proposed, it would be an effective method investigating the production of light (anti)nuclei in relativity heavy ion collision • Predict the light (anti)nuclei yield, transverse momentum and the rapidity distribution in pp collisions at √s = 7 and 14 TeV . • Studyed centrality dependence of light anti-nuclear produced in Au+Au collisions. • Discuss Scaling Properties of light antinuclei production in Au+Au coll.

  32. Thanks for yourattention!

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