Scaling Analysis of Chiral Phase Transition for Two Flavors of Kogut-Susskind Quarks

Report is made of a systematic scaling study of the finite-temperature chiral phase transition of two-flavor QCD with the Kogut-Susskind quark action based on simulations on $L^3\times 4$ ($L$=8, 12 and 16) lattices at the quark mass of $m_q=0.075,0.0375,0.02$ and 0.01. Our finite-size data show that a phase transition is absent for $m_q\ge 0.02$, and quite likely also at $m_q=0.01$. The scaling behavior of susceptibilities as a function of $m_q$ is consistent with a second-order transition at $m_q=0$. However, the exponents deviate from the O(2) or O(4) values theoretically expected.