1. Pornrad Srisawad Department of Physics, Naresuan University, Thailand Yu-Ming Zheng China Institute of Atomic Energy, Beijing China Azimuthal distributions of K+ mesons in heavy-ion collisions

2. 10/9/2015 2 Free template from www.brainybetty.com Introduction Introduction Kaons in dense matter Kaons in dense matter Kaon production in transport model Kaon production in transport model Probing in-medium kaon potential Probing in-medium kaon potential Summary Summary

3. 10/9/2015 3 Free template from www.brainybetty.com Introduction Kaons in dense hadronic matter are important Kaons in dense hadronic matter are important  a possible restoration of chiral symmetry  the properties of nuclear matter at high densities and temperatures. Extensive experimental efforts to search for the kaon in-medium potential in heavy ion collisions. Extensive experimental efforts to search for the kaon in-medium potential in heavy ion collisions. The azimuthal distribution is one of sensitive The azimuthal distribution is one of sensitive observes to extract information on in-medium properties at high densities. observes to extract information on in-medium properties at high densities.

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5. 10/9/2015 5 Free template from www.brainybetty.com Good probes for dense matter Kaons: Subthreshold Kaon production (E Lab < E thr ):

6. 10/9/2015 6 Free template from www.brainybetty.com The azimuthal distribution

7. 10/9/2015 7 Free template from www.brainybetty.com  Off plane : v 2 < 0  In – plane : v 2 > 0

8. 10/9/2015 8 Free template from www.brainybetty.com Dispersion relation : in-medium energy” Do kaons change their properties in dense matter?

9. 10/9/2015 9 Free template from www.brainybetty.com Density dependence of the in-medium kaon potential at zero momentum. IA: the impulse approximation [NPA 567 (1994) 937], BR potential KL potential

10. 10/9/2015 10 Free template from www.brainybetty.com Ratio of  (p+Au/p+C ) at T p = 2.3 GeV RBUU transport _ _ without Coulomb._._ only Coulomb …. Coulomb + 20 MeV _.._.. Coulomb + 40 MeV o data __ Coulomb + 20 MeV Eur. Phy. J. A 22 (2004) 301. Phys. Lett. B 540 (2002) 207.

11. 10/9/2015 11 Free template from www.brainybetty.com K + In-plane Flow Transverse K+ flow in 1.93 AGeV Ni + Ni reactions at impact parameter b≤4 fm. Data are from FOPI [Z. Phys. A352(95)355 (old) and Prog. Part. Nucl. Phys. 42 (99) 187(new)].

12. 10/9/2015 12 Free template from www.brainybetty.com Probing in-medium kaon potential Influence of in-medium K + potential on the kaon yields Influence of in-medium K + potential on the kaon yields for central (b=0) Au +Au and C + C reactions. [PPNP56(1)1] for central (b=0) Au +Au and C + C reactions. [PPNP56(1)1]

13. 10/9/2015 13 Free template from www.brainybetty.com The K + excitation functions in Au + Au (scaled by 10-1)and C + C reactions are compared to data from KaoS [PRL 82 (99) 1640); PRC 66 (02) 054604].

14. 10/9/2015 14 Free template from www.brainybetty.com K + rapidity distributions in Ni + Ni reactions at 1.93 AGeV. Data are from FOPI [NPA625 (97) 307] and KaoS [PLB 495 (2000) 26].

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16. 10/9/2015 16 Free template from www.brainybetty.com Au+Au at 1.5 A GeV data The azimuthal distribution K + Out of-plane Flow

17. 10/9/2015 17 Free template from www.brainybetty.com ExperimentdataCalculation with K + N Calculation without K + N transverse flow (v 1 ) 0.04±0.01-0.015±0.0016-0.006±0.0013 Elliptic flow v 2 v 2-0.09±0.03-0.043±0.0016-0.03±0.0013

18. 10/9/2015 18 Free template from www.brainybetty.com Ni+Ni at 1.93 A GeV data The azimuthal distribution

19. 10/9/2015 19 Free template from www.brainybetty.com ExperimetDataCalculation with K + N Calculation without K + N transverse flow (v 1 ) -0.01±0.01 - 0.013±0.0015 -0.006±0.0014 Elliptic-flow (v 2 ) -0.05±0.03 - 0.040±0.0016 -0.02±0.0014

20. 10/9/2015 20 Free template from www.brainybetty.com Summary  K + production can be used to probe the in- medium kaon potential, and consequently to probe an expected partial restoration of chiral symmetry at supra-normal nuclear densities.  Most transport simulations reproduce corresponding data only when in-medium potentials are included The azimuthal distribution is one of sensitive observes to extract information on in-medium properties at high densities.

21. 10/9/2015 21 Free template from www.brainybetty.com  We have analyzed the azimuthal distributions of K + mesons produced in Au+Au reactions at 1.5 A GeV and in Ni + Ni reactions at 1.93 A GeV within the QMD model.  Calculated results with a in-medium K + N potential can reasonably describe the features of KaoS data.This indicates that the azimuthal distribution is one of sensitive probes to extract information on in-medium properties of K + mesons at high densitis.

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