A Very Light Dilaton

TL;DR

This paper introduces a perturbative model mimicking walking technicolor, where spontaneous scale symmetry breaking leads to a light dilaton, with its mass tunable independently of interaction strength.

Contribution

It presents a novel perturbative framework showing spontaneous scale symmetry breaking and dilaton emergence, distinct from traditional non-perturbative approaches.

Findings

Light dilaton mass is adjustable without weakening interactions.

Model exhibits two phases with different RG trajectory behaviors.

Spontaneous symmetry breaking occurs before reaching the IR fixed point.

Abstract

We present a completely perturbative model that displays behavior similar to that of walking technicolor. In one phase of the model RG-trajectories run towards an IR-fixed point but approximate scale invariance is spontaneously broken before reaching the fixed point. The trajectories then run away from it and a light dilaton appears in the spectrum. The mass of the dilaton is controlled by the "distance" of the theory to the critical surface, and can be adjusted to be arbitrarily small without turning off the interactions. There is a second phase with no spontaneous symmetry breaking and hence no dilaton, and in which RG trajectories do terminate at the IR-fixed point.