Many flavor approach to study the critical point in finite density QCD

Abstract

We discuss the QCD critical point at finite density through th e study of many flavor QCD, in which two light flavors and Nf massive flavors exist. Performing simulations of QCD with tw o flavors of improved Wilson fermions, we calculate the probability distribution function of a generalized plaquette in many flavor QCD at finite temperature and density . The dynamical effects of massive flavors and the chemical potential are incorporated using th e reweighting technique. From the shape of the distribution functions, we determine the criti cal surface separating the first order transition and crossover regions in the parameter space of the light and massive quark masses and the chemical potentials. It is found that the critical massi ve quark mass becomes larger as the chemical potential increases in the (2+ Nf) flavor QCD. The indication to the (2+1) flavor QCD is then discussed.