Transition Temperature of Two-Degenerate-Flavour QCD in the Chiral Limit

We present the results for the transition temperature of quantum chromodynamics (QCD) with two degenerate flavours (N_f=2) of Wilson quarks. On lattice 8³×4 with 4 representing the temporal extent, by using the Ferrenberg--Swendsen reweighting method, we determine the critical β=6/g² where the transition occurs, g is the coupling constant. On lattice 8²×20×4, by using the axial vector Ward--Takahashi identity, we calculate the current quark mass am_q, a is the lattice spacing. Assuming the O(4) scaling, the critical β in the chiral limit is determined. We calculate the ρ meson mass am_ρ at zero temperature on lattice 8³×20. By using the experimental ρ meson mass to set the scale, we obtain 194(1)MeV for the transition temperature in the chiral limit.