Marginal Breaking of Conformal SUSY QCD

TL;DR

This paper demonstrates a 4D supersymmetric QCD model where conformal symmetry breaking via an almost marginal operator produces a light dilaton and suppressed vacuum energy, with detailed analysis of vacuum stability and dilaton mass.

Contribution

It provides a concrete example of the Contino-Pomarol-Rattazzi mechanism in SUSY QCD, including vacuum stabilization and dilaton mass computation.

Findings

The singlet meson reaches the unitarity bound in the dual theory.

Vacuum stability is achieved with soft breaking terms.

The dilaton mass is primarily determined by the almost marginal coupling.

Abstract

We provide an example of a 4D theory that exhibits the Contino-Pomarol-Rattazzi mechanism, where breaking conformal symmetry by an almost marginal operator leads to a light pseudo-Goldstone boson, the dilaton, and a parametrically suppressed contribution to vacuum energy. We consider SUSY QCD at the edge of the conformal window and break conformal symmetry by weakly gauging a subgroup of the flavor symmetry. Using Seiberg duality we show that for a range of parameters the singlet meson in the dual theory reaches the unitarity bound, however, this theory does not have a stable vacuum. We stabilize the vacuum with soft breaking terms, compute the mass of the dilaton, and determine the range of parameters where the leading contribution to the dilaton mass is from the almost marginal coupling.