Chemical freeze-out in Hawking-Unruh radiation and quark-hadron transition

The proposed analogy between hadron production in high-energy collisions and Hawking-Unruh radiation process in the black holes shall be extended. This mechanism provides a theoretical basis for the freeze-out parameters, the temperature (\(T\)) and the baryon chemical potential (\(\mu\)), characterizing the final state of particle production. The results from charged black holes, in which the electric charge is related to \(\mu\), are found comparable with the phenomenologically deduced parameters from the ratios of various particle species and the higher-order moments of net-proton multiplicity in thermal statistical models and Polyakov linear-sigma model. Furthermore, the resulting freeze-out condition \(\langle E\rangle/\langle N\rangle\simeq 1~\)GeV for average energy per particle is in good agreement with the hadronization process in the high-energy experiments. For the entropy density (\(s\)), the freeze-out condition \(s/T^3\simeq7\) remains valid for \(\mu\lesssim 0.3~\)GeV. Then, due to the dependence of \(T\) on \(\mu\), the values of \(s/T^3\) increase with increasing \(\mu\). In accordance with this observation, we found that the entropy density remains constant with increasing \(\mu\). Thus, we conclude that almost no information is going lost through Hawking-Unruh radiation from charged black holes. It is worthwhile to highlight that the freeze-out temperature from charged black holes is determined independent on both freeze-out conditions