QCD transition temperature: approaching the continuum on the lattice

In order to clarify the source of the discrepancy between our previous transition temperature determination [Phys. Lett. B 643, 46 (2006)] and that of the Bielefeld-Brookhaven-Columbia-Riken collaboration we improved our calculations by taking even smaller lattice spacings (N_t = 12 and N_t = 16 at one point) and by using physical quark masses also for the T = 0 quantities. In addition to the kaon decay constant used for scale setting we determine four quantities (masses of the Ω baryon, k*(892) and φ{symbol}(1020) mesons and the pion decay constant) which are found to agree with experiment. This implies that - independently of which of these quantities is used to set the overall scale - the same results are obtained within a few percent. At finite temperature we use finer lattices down to a ≲ 0.1 fm. Our new results confirm completely our previous findings. We compare the results with those of the 'hotQCD' collaboration.