TY  - JOUR
A1  - Motornenko, Anton
A1  - Steinheimer, Jan
A1  - Vovchenko, Volodymyr
A1  - Stock, Reinhard
A1  - Stöcker, Horst
T1  - Ambiguities in the hadro-chemical freeze-out of Au+Au collisions at SIS18 energies and how to resolve them
T2  - Physics Letters B
N2  - The thermal fit to preliminary HADES data of Au+Au collisions at sNN=2.4 GeV shows two degenerate solutions at T≈50 MeV and T≈70 MeV. The analysis of the same particle yields in a transport simulation of the UrQMD model yields the same features, i.e. two distinct temperatures for the chemical freeze-out. While both solutions yield the same number of hadrons after resonance decays, the feeddown contribution is very different for both cases. This highlights that two systems with different chemical composition can yield the same multiplicities after resonance decays. The nature of these two minima is further investigated by studying the time-dependent particle yields and extracted thermodynamic properties of the UrQMD model. It is confirmed, that the evolution of the high temperature solution resembles cooling and expansion of a hot and dense fireball. The low temperature solution displays an unphysical evolution: heating and compression of matter with a decrease of entropy. These results imply that the thermal model analysis of systems produced in low energy nuclear collisions is ambiguous but can be interpreted by taking also the time evolution and resonance contributions into account.
Y1  - 2021
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/69872
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-698724
SN  - 1873-2445
SN  - 0370-2693
VL  - 822.2021
IS  - 136703
PB  - Elsevier
CY  - Amsterdam
ER  -