Exploring QCD phase diagram at vanishing baryon density on the lattice
I report on the current status of QCD phase diagram at vanishing baryon density. I focus on the QCD phase diagram with three degenerate quark flavor using Highly Improved Staggered Quarks on NT = 6 lattices. No evidence of a first order phase transition in the pion mass window of 80 ≲ mπ ≲ 230 MeV is found. The pion mass at the critical point where the chiral first order phase transition ends is estimated to be mπc ≲ 45 MeV.