Supersymmetry Breaking and Moduli Stabilization with Anomalous U(1) Gauge Symmetry

TL;DR

The paper studies how an anomalous U(1)_A gauge symmetry interacts with Green-Schwarz modulus stabilization in KKLT-type compactifications. It shows that the low-energy soft terms receive comparable contributions from GS modulus mediation, anomaly mediation, and U(1)_A mediation, naturally yielding a mirage mediation pattern for superpartner masses. A key result is that the D-term uplift from U(1)_A cannot uplift a SUSY-breaking vacuum to de Sitter when the gravitino is much lighter than the Planck scale, forcing the use of explicit uplifting (e.g., anti-brane). The authors provide a concrete KKLT-based model stabilizing the GS modulus with a singlet X and a hidden sector, demonstrating how the three mediation channels combine and how the mirage scale can be tuned (with α = 1 in minimal sequestered setups or α ≈ 2 in other cases), yielding distinctive phenomenology for MSSM-like theories.

Abstract

We examine the effects of anomalous U(1)_A gauge symmetry on soft supersymmetry breaking terms while incorporating the stabilization of the modulus-axion multiplet responsible for the Green-Schwarz (GS) anomaly cancellation mechanism. In case of the KKLT stabilization of the GS modulus, soft terms are determined by the GS modulus mediation, the anomaly mediation and the U(1)_A mediation which are generically comparable to each other, thereby yielding the mirage mediation pattern of superparticle masses at low energy scale. Independently of the mechanism of moduli stabilization and supersymmetry breaking, the U(1)_A D-term potential can not be an uplifting potential for de Sitter vacuum when the gravitino mass is smaller than the Planck scale by many orders of magnitude. We also discuss some features of the supersymmetry breaking by red-shifted anti-brane which is a key element of the KKLT moduli stabilization.