Transverse Pressure and Strangeness Dynamics in Relativistic Heavy Ion Reactions

Abstract

Transverse hadron spectra from proton-proton, proton-nucleus and nucleus-nucleus collisions from 2 AGeV to 21.3 ATeV are investigated within two independent transport approaches (HSD and UrQMD). For central Au+Au (Pb+Pb) collisions at energies above $E_{\mathrm{lab}}\sim$ 5 AGeV, the measured $K^{\pm }$ transverse mass spectra have a larger inverse slope parameter than expected from the default calculations. The additional pressure - as suggested by lattice QCD calculations at finite quark chemical potential ${\mu }_q$ and temperature $T$ - might be generated by strong interactions in the early pre-hadronic/partonic phase of central Au+Au (Pb+Pb) collisions. This is supported by a non-monotonic energy dependence of $v_2/<p_T>$ in the present transport model.

Comments: Proceedings of Strange Quark Matter 2004