  The flavor dependence of the QCD phase diagram presents universal properties
in the heavy quark limit. For the wide class of models where the quarks are
treated at the one-loop level, we show, for arbitrary chemical potential, that
the flavor dependence of the critical quark masses-for which the
confinement-deconfinement transition is second order-is insensitive to the
details of the (confining) gluon dynamics and that the critical temperature is
constant along the corresponding critical line. We illustrate this with
explicit results in various such one-loop models studied in the literature:
effective matrix models for the Polyakov loop, the Curci-Ferrari model, and a
recently proposed Gribov-Zwanziger-type model. We further observe that the
predictions which follow from this one-loop universality property are well
satisfied by different calculations beyond one-loop order, including lattice
simulations. For degenerate quarks, we propose a simple universal law for the
flavor dependence of the critical mass, satisfied by all approaches.
