A quasiparticle equation of state with a phenomenological critical point

We propose a hybrid parameterization of a quasiparticle equation of state, where a critical point is implemented phenomenologically. In this approach, a quasiparticle model with finite chemical potential is used to describe the quark-gluon plasma phase by fitting to the lattice quantum chromodynamics data at high temperature. On the other hand, the hadronic resonance gas model with excluded volume correction is employed for the hadronic phase. An interpolation scheme is implemented so that the phase transition is a smooth crossover when the chemical potential is smaller than a critical value, or otherwise approximately of the first order according to Ehrenfest's classification. Also, the thermodynamic consistency is guaranteed for the equation of state related to both the quasiparticle model and the implementation of the critical point. (author)