by E. S. Bowman and J. I. Kapusta in Physical Review C 79, 015202 (2009).

We employ a simple effective model to study the chiral dynamics of two flavors of quarks at finite temperature and density. In particular, we determine the phase diagram in the plane of temperature and baryon chemical potential as a function of the pion mass. An interesting phase structure occurs that results in zero, one, or two critical points depending on the value of the vacuum pion mass.