QUANTUM CHROMODYNAMICS WITH VARIOUS NUMBER OF FLAVORS

The phase structure of QCD with various number of flavors is studied for Wilson quarks. For the case of N(F) = 3 we find that the finite temperature deconfining transition is of first order in the chiral limit on an N(t) = 4 lattice. Together with our previous results that the deconfining transition in the chiral limit is continuous for N(F) = 2 and is first order for N(F) = 6, the order of the transition is found to be consistent with a prediction of universality. The case of SU(2) QCD is also studied in the strong coupling limit and the phase structure is found to be quite similar to the case of SU(3): There exists a critical number of flavors N(F)* and for N(F) greater-than-or-equal-to N(F)* the confinement is broken even in the strong coupling limit for light quarks. N(F)* = 3 corresponding to 7 for SU(3).