A Light Dilaton in Gauge Theories?

(By Bob Holdom, John Terning. Published in Phys.Lett.187B:357,1987.)

We study gauge theories having a slowly varying running coupling and chiral symmetry breaking. It has been suggested that such theories contain a light dilaton, a pseudo-Goldstone boson associated with approximate scale invariance. We calculate its mass by studying the scaling properties of the effective action describing chiral symmetry breaking. We also consider the effect of a physical high energy cutoff as motivated in a technicolor context. Our results indicate that a light dilaton is unlikely.