Influence of strange quarks on the QCD phase diagram and chemical freeze-out

We study the influence of strange quarks on the QCD phase diagram and the location of the chemical freeze-out. We compare the lattice results on the QCD phase diagram for two and three flavours with the hadron resonance gas model (HRGM) calculations. Taking into account the truncations in the Taylor-expansion of the expression of energy density ε as done in lattice calculations, we find that HRGM under the condition of constant ε describes very well the lattice QCD phase diagram. We study the chemical freeze-out parameters according to the entropy density s. The s value has been taken from the lattice QCD calculations for two and three flavours. We find that the condition s/T3 = 5 is excellent in reproducing the experimentally estimated parameters of the chemical freeze-out for two flavours. For three flavours the condition is s/T3 = 7