Strangeness production in low energy heavy ion collisions via Hagedorn resonances

Abstract

Background: Statistical models are successfully used to describe particle multiplicities in (ultra)relativistic heavy ion collisions. Transport models usually lack the ability to describe special aspects of the results of these experiments, as the fast equilibration and some multiplicity ratios. Purpose: An alternative, unorthodox picture of the dynamics of heavy ion collisions is developed using the concept of Hagedorn states. Method: A prescription of the bootstrap of Hagedorn states respecting the conserved quantum numbers baryon number B, strangeness S, isospin I is implemented into the GiBUU transport model. Results: Using a strangeness saturation suppression factor suitable for nucleon-nucleon collisions, recent experimental data for the strangeness production by the HADES collaboration in Au + Au and Ar + KCl is reasonably well described. The experimentally observed exponential slopes of the energy distributions are nicely reproduced. Conclusions: A dynamical model using Hagedorn resonance states, supplemented by a strangeness saturation suppression factor, is able to explain essential features (multiplicities, exponential slope) of experimental data for strangeness production in nucleus-nucleus collisions close to threshold.