Asymmetric Origin for Gravitino Relic Density in the Hybrid Gravity-Gauge Mediated Supersymmetry Breaking

TL;DR

This paper introduces a hybrid gravity-gauge mediated supersymmetry breaking model with a gravitino mass around several GeV, addressing collider constraints, dark matter relic density, and flavor anomalies.

Contribution

It proposes a novel asymmetric origin for gravitino relic density linked to asymmetric metastable particles, and explores models with vector-like particles or U(1)_R symmetry.

Findings

Relaxes LHC constraints on supersymmetry due to heavy colored particles.

Provides a natural explanation for the LHCb anomaly via small gravity mediation.

Achieves gravitino relic density consistent with asymmetric dark matter and baryon densities.

Abstract

We propose the hybrid gravity-gauge mediated supersymmetry breaking where the gravitino mass is about several GeV. The strong constraints on supersymmetry viable parameter space from the CMS and ATLAS experiments at the LHC can be relaxed due to the heavy colored supersymmetric particles, and it is consistent with null results in the dark matter (DM) direct search experiments such as XENON100. In particular, the possible maximal flavor and CP violations from the relatively small gravity mediation may naturally account for the recent LHCb anomaly. In addition, because the gravitino mass is around the asymmetric DM mass, we propose the asymmetric origin of the gravitino relic density and solve the cosmological coincident problem on the DM and baryon densities \Omega_{\rm DM}:\Omega_{B}\approx 5:1. The gravitino relic density arises from asymmetric metastable particle (AMP) late decay. However, we show that there is no AMP candidate in the minimal supersymmetric Standard Model (SM) due to the robust gaugino/Higgsino mediated wash-out effects. Interestingly, AMP can be realized in the well motivated supersymmetric SMs with vector-like particles or continuous U(1)_R symmetry. Especially, the lightest CP-even Higgs boson mass can be lifted in the supersymmetric SMs with vector-like particles.