Phase structure of lattice QCD at finite temperature for 2+1 flavors of   Kogut-Susskind quarks
  We report on a study of the finite-temperature chiral transition on an $N_t=4$ lattice for 2+1 flavors of Kogut-Susskind quarks. We find the point of physical quark masses to lie in the region of crossover, in agreement with results of previous studies. Results of a detailed examination of the $m_{u,d}=m_s$ case indicate vanishing of the screening mass of $\sigma$ meson at the end point of the first-order transition. 
JLQCD Collaboration: S. Aoki, M. Fukugita, S. Hashimoto, K-I.   Ishikawa, N. Ishizuka, Y. Iwasaki, K. Kanaya, T. Kaneda, S. ...