Gauge vs. Gravity mediation in models with anomalous U(1)'s
E. Dudas, Y. Mambrini, S. Pokorski, A. Romagnoni, M. Trapletti
TL;DR
The paper analyzes gauge versus gravity mediation in string-inspired supergravity with anomalous U(1) factors, showing that moduli stabilization and moduli-dependent FI terms prevent robust pure gauge mediation and often drive the system toward hybrid gauge–gravity mediation regimes. Through gauged Polonyi, Fayet–Ochary, and FI/Fayet–Polony constructions, it demonstrates that SUSY vacua typically require a non-small SUSY-breaking field $S$ and that moduli stabilization cannot be neglected, which constrains gauge mediation dominance. A broad class of hybrid models with extended messenger sectors is then constructed to realize metastable SUSY-breaking vacua with mixed mediation, offering phenomenologically interesting spectra potentially testable at the LHC. The study identifies intrinsic limitations of gauge mediation in the presence of anomalous U(1) symmetries, and highlights viable hybrid scenarios where gauge mediation is present but not exclusive, tightly tied to FI terms and modulus dynamics.
Abstract
In an attempt to implement gauge mediation in string theory, we study string effective supergravity models of supersymmetry breaking, containing anomalous gauge factors. We discuss subtleties related to gauge invariance and the stabilization of the Green-Schwarz moduli, which set non-trivial constraints on the transmission of supersymmetry breaking to MSSM via gauge interactions. Given those constraints, it is difficult to obtain the dominance of gauge mediation over gravity mediation. Furthermore, generically the gauge contributions to soft terms contain additional non-standard terms coming from D-term contributions. Motivated by this, we study the phenomenology of recently proposed hybrid models, where gravity and gauge mediations compete at the GUT scale, and show that such a scenario can respect WMAP constraints and would be easily testable at LHC.