Supersymmetry Breaking and Composite Extra Dimensions

TL;DR

The paper addresses the SUSY flavor problem by proposing a 4D realization of sequestering through a strongly coupled superconformal hidden sector, interpreted as a composite analogue of extra dimensions via AdS/CFT. A prototype SCFT, based on SUSY QCD in the conformal window, yields large anomalous dimensions that suppress dangerous hidden-visible contact terms, allowing anomaly mediation to dominate the visible-sector SUSY breaking. An explicit 4D model using an $SU(2)$ gauge theory with 8 fundamentals demonstrates moduli stabilization, spontaneous conformal breaking, and SUSY breaking via a Polonyi-type sector, with quantitative FCNC suppression criteria and sample mass scales. The work shows that sequestering and anomaly mediation can be realized without extra dimensions, offering a tractable path to flavor-safe SUSY phenomenology and avenues for further extensions to gaugino/radion mediation and natural hierarchy generation.

Abstract

We study supergravity models in four dimensions where the hidden sector is superconformal and strongly-coupled over several decades of energy below the Planck scale, before undergoing spontaneous breakdown of scale invariance and supersymmetry. We show that large anomalous dimensions can suppress Kahler contact terms between the hidden and visible sectors, leading to models in which the hidden sector is "sequestered" and anomaly-mediated supersymmetry breaking can naturally dominate, thus solving the supersymmetric flavor problem. We construct simple, explicit models of the hidden sector based on supersymmetric QCD in the conformal window. The present approach can be usefully interpreted as having an extra dimension responsible for sequestering replaced by the many states of a (spontaneously-broken) strongly-coupled superconformal hidden sector, as dictated by the AdS/CFT correspondence.