Lawrence Berkeley National Laboratory

We investigate the chiral phase transition in SU(N) gauge theories as the number of quark flavors, Nf, is varied. We argue that the transition takes place at a large enough value of Nf so that it is governed by the infrared fixed point of the Nf function. We study the nature of the phase transition analytically and numerically, and discuss the spectrum of the theory as the critical value of Nf is approached in both the symmetric and broken phases. Since the transition is governed by a conformal fixed point, there are no light excitations on the symmetric side. We extend previous work to include higher order effects by developing a renormalization group estimate of the critical coupling.