Information entropy for central $^{197}$Au+$^{197}$Au collisions with the ultrarelativistic quantum molecular dynamics model

This study investigates the multiplicity information entropy of hadrons, anti-hadrons, baryons, and net-protons in central $^{197}$Au+$^{197}$Au collisions with impact parameters of 0$-$3 fm, using the ultrarelativistic quantum molecular dynamics model (UrQMD) across various center-of-mass energies ($\sqrt{s_{\rm NN}}$) from 5.0 to 54.4 GeV. Our simulations employ hydrodynamic modes with different equations of state (EoS) and a default mode without hydrodynamics. The results reveal that the information entropies of baryons and net-protons are sensitive to the selected EoS. In particular, enhancements of the information entropies around $\sqrt{s_{\rm NN}} \sim 30$ GeV, especially with chiral hadron gas and Bag model EoS, indicate a phase transition or critical endpoint behavior. These findings highlight the importance of the EoS in understanding the thermodynamic properties of matter produced in high-energy collisions.