Critical point in finite density lattice QCD by canonical approach

Abstract

We propose a method to find the QCD critical point at finite density calculating the canonical partition function ${\mathcal{Z}}_{\mathrm{C}}(T,N)$ by Monte-Carlo simulations of lattice QCD, and analyze data obtained by a simulation with two-flavor p4-improved staggered quarks with pion mass $m_{\pi }\approx 770\mathrm{MeV}$. It is found that the shape of an effective potential changes gradually as the temperature decreases and a first order phase transition appears in the low temperature and high density region. This result strongly suggests the existence of the critical point in the $(T,{\mu }_q)$ phase diagram.

Comments: 4 pages, 2 figures, To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennessee