Kaons and antikaons in hot and dense hadronic matter -: art. no. 044904

The medium modification of kaon and antikaon masses, compatible with low-energy kaon-nucleon scattering data, are studied in a chiral SU(3) model. The mutual interactions with baryons in hot hadronic matter and the effects from the baryonic Dirac sea on the K(<<(K)over bar>) masses are examined. The in-medium masses from the chiral SU(3) effective model are compared to those from chiral perturbation theory. Furthermore, the influence of these in-medium effects on kaon rapidity distributions and transverse energy spectra, as well as the K,(K) over bar flow pattern in heavy-ion collision experiments at 1.5-2 A GeV are investigated within the hadron-string-dynamics transport approach. Detailed predictions on the transverse momentum and rapidity dependence of directed flow v(1) and the elliptic flow v(2) are provided for Ni+Ni at 1.93A GeV within the various models, that can be used to determine the in-medium K+/- properties from the experimental side in the near future.