Chiral phase transition at finite temperature and conformal dynamics in large Nf QCD

We investigate the chiral phase transition at finite temperature (T) in colour SU(Nc=3) Quantum Chromodynamics (QCD) with a variable number of fermions Nf in the fundamental representation by using lattice QCD. For Nf=6 we study the approach to asymptotic scaling by considering lattices with several temporal extensions Nt. We then extract the dimensionless ratio Tc/ΛL (ΛL=lattice Lambda-parameter) for Nf=6 and Nf=8, the latter relying on our earlier results. Further, we collect the (pseudo) critical couplings βLc for the chiral phase transition at Nf=0 (quenched), and Nf=4 at a fixed Nt=6. The results are consistent with enhanced fermionic screening at larger Nf. The ratio Tc/ΛL depends very mildly on Nf in the Nf=0-4 region, starts increasing at Nf=6, and becomes significantly larger at Nf=8, close to the edge of the conformal window. We discuss interpretations of these results as well as their possible interrelation with preconformal dynamics in the light of a functional renormalization group analysis.