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Helmut Oeschler Darmstadt University of Technology

Strangeness Production at 1 -2 AGeV. Helmut Oeschler Darmstadt University of Technology. Erice, September 2008. Results mainly from the KaoS Collaboration Phys. Rev. C (2007) Detailed IQMD Calculations Phys. Rep. in preparation with C. Hartnack, J. Aichelin. Au+Au. C+C. u d s. L. u

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Helmut Oeschler Darmstadt University of Technology

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  1. Strangeness Production at 1 -2 AGeV Helmut Oeschler Darmstadt University of Technology Erice, September 2008

  2. Results mainly from the KaoS Collaboration Phys. Rev. C (2007) Detailed IQMD Calculations Phys. Rep. in preparation withC. Hartnack, J. Aichelin

  3. Au+Au C+C

  4. u d s L u d u u d d p u d d n n s u s u K+ K+ s u u d u K- u d u d d u p p n d d u n u d s u d u u d d u d s p S0 L n u u s u d u s u K- p0 K+ p+ K-absorption Creation of Strange Mesons

  5. Mean free path of Kaons and Antikaons mean free path at ρ0: λ(π) = 0.3 fm λ(K+) = 5 fm λ(K-) = 0.8 fm K- absorption by strangeness exchange reactions: K- p → Y πo K+: "nearly" undisturbed messengers

  6. K+ production below and at threshold Comparision with data IQMD calculations, Au+Au central collisions

  7. Before getting started: Are the pions okay? Data: A. Wagner et al., KaoS N/Z ratio and Coulomb

  8. KaoS Collaboration, PRC 75 (2007) K- and K+ are linked Is s exch. in equil.? Law-of-mass action J. Cleymans et al., PLB 603(2004) M ~ Aγ A. Förster, F. Uhlig et al., PRL 91 (2003)

  9. IQMD C. Hartnack et al., PRL 93 (2004)

  10. Time Evolution of K+ and K- Production Strangeness exchange dominates! Only 20% of all K- survive! C.Hartnack, H.O., J. Aichelin, PRL 90(2003)

  11. Kaon Spectra PRC 75 (2007)

  12. Trend of the K+ slopes

  13. What determines the shape of the K+ spectra? According to IQMD calculations

  14. Slopes of K- are lower!

  15. Influence on K- spectra Au+Au: only 20% survive about 30% of those do not scatter

  16. K+ yield determined at production K+ spectral shape at last collision K- yield and spectral shape at last collision

  17. Out-of-plane Emission Ni+Ni 1.93 AGeV (F .Uhlig, PRL 95 (2005))

  18. IQMD Calculations (C. Hartnack et al.)

  19. F. Uhlig, et al., KaoS, PRL 95 (2005)

  20. Latest from KaoS: v2 as a function of pt Au+Au 1.5 AGeV, M. Ploskon, KaoS to be published! IQMD calculations, C. Hartnack

  21. T. Gaitanos et al., EPJ A12, 421 (2001) The nuclear equation of state Densities reached in Au+Au ≈ 2-3 ρ0, in C+C much less

  22. KaoS Collaboration C. Sturm et al., PRL 86 (2001) A.Förster et al., PR C75 (2007) RQMD: C. Fuchs et al., PRL 86 (2001) IQMD: C. Hartnack et al., PRL 96 (2006)

  23. Results confirmed also with several calculations and other observables! C. Hartnack, HO, J. Aichelin, PRL 96 (2006)

  24. K+ yield determined at production which is around twice ρ0 • K+ spectra dominated by scattering, some influence by KN potential • K- yield dominated by strangeness exchange at densities around ρ0 • K- spectra influenced by absorption, scattering and potential

  25. Best observable for KN Potential? K+(AuAu)/K+(CC) * * * EOS! Most uncertainties cancel

  26. Grazie!

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