Anomalous U(1) as a mediator of Supersymmetry Breaking

TL;DR

The paper shows that an anomalous U(1) gauge symmetry can mediate SUSY breaking, leveraging a Fayet-Iliopoulos term $\xi$ from Green–Schwarz anomaly cancellation to realize flat-limit breaking and avoiding the Polonyi problem. In supergravity, SUSY breaking is transmitted to the MSSM via both gravity and the $D$-term, producing a distinctive soft-mass hierarchy with scalar contributions $ abla m^2_Q = q_i m^2$ and gaugino masses $m_ abla \\sim ε m$ where $ε = ξ / M_P^2$. A dynamical origin for the scale $m$ is provided through a hidden SU(2) sector, generating $m$ and enabling loop-induced gaugino masses $m_λ \\sim m/(16π^2)$, while the first-two-family squarks can be heavy to suppress FCNC and CP violation. The framework offers a compelling alternative to purely gravity-mediated SUSY breaking, with testable implications for the superpartner spectrum and potential connections to fermion mass hierarchies, all while sidestepping the Polonyi problem.

Abstract

We point out that an anomalous gauge U(1) symmetry is a natural candidate for being the mediator and messenger of supersymmetry breaking. It facilitates dynamical supersymmetry breaking even in the flat limit. Soft masses are induced by both gravity and the U(1) gauge interactions giving an unusual mass hierarchy in the sparticle spectrum which suppresses flavor violations. This scenario does not suffer from the Polonyi problem.