Curvature of Pseudocritical Transition Line for Two-Flavor QCD with Improved Kogut–Susskind Quarks

The results on the curvature of a pseudocritical transition line for two-flavor QCD through lattice simulations are presented. The simulations are carried out with Symanzik-improved gauge action and Asqtad fermion action on a lattice 12^3\times4 at quark mass am=0.010. At the imaginary chemical potentials a\mu__\rm I=0.050, 0.150, 0.200, 0.225 and 0.250, we investigate the chiral condensate \bar\psi\psi, plaquette variable P and imaginary part of Polyakov loop \rm Im(L) and their susceptibilities. Analytic continuation from an imaginary chemical potential to a real one is used to obtain the expression for transition temperature as a function of the chemical potential. The curvature is 0.0326(46).