We report the first case study of the phase diagram of $2+1$ flavor strongly interacting matter in $\beta$ equilibrium, using the Polyakov-Nambu-Jona-Lasinio model. Physical characteristics of relevant thermodynamic observables have been discussed. A comparative analysis with the corresponding observables in the Nambu-Jona-Lasinio model is presented. We find distinct differences between the models in terms of a number of thermodynamic quantities like the speed of sound, specific heat, various number densities, as well as entropy. The present study is expected to give us a better insight into the role that the superdense matter created in heavy-ion collision experiments plays in our understanding of the properties of matter inside the core of supermassive stars in the Universe.

• Received 29 July 2011

DOI:https://doi.org/10.1103/PhysRevD.86.096006