Thermal hadron production in relativistic nuclear collisions

Abstract

We present the status of the description of hadron production in central nucleus-nucleus collisions within the statistical model . Extending previous studies by inclusion of very high-mass resonances (m>2 GeV), and the up-to-now neglected scalar $σ$ meson leads to an improved description of the data. In particular, the hitherto poorly reproduced energy dependence of the K+/pi+ ratio at SPS energies ("the horn") is now well described through the connection to the hadronic mass spectrum and, implicitly, Hagedorn's limiting temperature.

8 pages, 4 figures (v2: typo in Eq.1 corrected); to appear in the proceedings of the IV Workshop on Particle Correlations and Femtoscopy (WPCF2008), Krakow, 2008; datafiles with calculations available at http://www-linux.gsi.de/~andronic/physics/s/s.html