Speaker
Description
The correlations between mean transverse momentum and the total charged multiplicity in the relativistic high-energy ultra-central heavy-ion collisions have been recognized at the LHC energies. This type of correlation can be understood associated with the thermodynamic response between the variations of energy density and variations of pressure, in a uniform thermal system that effectively captures the identical thermodynamical properties, in particular, the speed of sound. In this talk, we extend the analysis to cases with finite baryon densities, regarding the QCD systems created at lower collision energies. We realize that the realistic fireball evolves approximately adiabatically, with a constant ratio of total entropy over total baryon number, $S/N_B$. Such a condition constrains the effective thermodynamic response, which not only modifies the speed of sound values, but also provide an essential mechanism that significantly suppresses the mean transverse momentum fluctuations in the vicinity of QCD critical end point.