Genuine Dilatons in Gauge Theories

A genuine dilaton sigma allows scales to exist even in the limit ofexactconformal invariance. In gauge theories, these may occur at an infrared fixed point (IRFP)alpha IRthrough dimensional transmutation. These large scales at alpha IRcan be separated from small scales produced by theta mu mu, the trace of the energy-momentum tensor. For quantum chromodynamics (QCD), the conformal limit can be combined with chiralSU(3)xSU(3)symmetry to produce chiral-scale perturbation theory chi PT sigma, withf0(500)as the dilaton. The technicolor (TC) analogue of this is crawling TC: at low energies, the gauge coupling alpha goes directly to (but does not walk past)alpha IR, and the massless dilaton at alpha IRcorresponds to a light Higgs boson at alpha less than or similar to alpha IR. It is suggested that theW +/- andZ0bosons set the scale of the Higgs boson mass. Unlike crawling TC, in walking TC,theta mu mu producesallscales, large and small, so it is hard to argue that its "dilatonic" candidate for the Higgs boson is not heavy.