Chiral phase diagram of strongly interacting matter at finite volume

At extremely high temperature T～200 Me V and low chemical potentialμ,the quarks and gluons get released from the nucleon and form the quark-gluon plasma(QGP)state,which is accessible in the heavy ion collisions(HIC)globally[1,2].Theoretically,ab initio lattice QCD simulation found the transition from hadrons to QGP at lowμis continuous crossover instead of phase transition.In this connection,RHIC is running the beam energy scan program to look into the territory with higherμ[3].One important goal is to determine if there is the first order phase transition as expected by many model studies and locate the critical end point(CEP)if it exists.