PUB - Publikationen an der Universität Bielefeld

We present studies of universal properties of the chiral phase transition in$N_f$=2+1 QCD based on the simulations using Highly Improved Staggered fermionson lattices with temporal extent $N_\tau$=6. We analyze the quark mass andvolume dependence of the chiral condensates and chiral susceptibilities in QCDwith two degenerate light quarks and a strange quark. The strange quark mass ischosen to be fixed to its physical value ($m^{phy}_s$) and five values of lightquark masses ($m_l$) that are varied in the interval 1/20$\gtrsim m_l/m^{phy}_s\gtrsim$1/80. Here various quark masses correspond to pseudo Goldstone pionmasses ranging from about 160 MeV to about 80 MeV. The O(N) scaling of chiralobservables and the influence of universal scaling on physical observables inthe region of physical quark mass values are also discussed.