Physical spectrum of conformalSU(N)gauge theories

Abstract

We investigate the physical spectrum of vector-like $\mathrm{SU}(N)$ gauge theories with infrared coupling close to but above the critical value for a conformal phase transition. We use dispersion relations, the momentum dependence of the dynamical fermion mass and resonance saturation. We argue that the second spectral function sum rule is substantially affected by the continuum contribution, allowing for a reduction of the axial-vector--vector mass splitting with respect to QCD-like theories. Possible consequences for technicolor theories are described.