Soft RPV Through the Baryon Portal

TL;DR

This paper proposes a supersymmetric model with baryonic R-parity violation arising from soft SUSY-breaking interactions, suppressing leptonic RPV to evade proton decay constraints, and explores its collider and dark matter implications.

Contribution

It introduces a novel mechanism for baryonic RPV via a hidden R-breaking sector and a heavy mediator, avoiding new hierarchies and enabling viable dark matter candidates.

Findings

RPV couplings are loop-suppressed, reducing collider signatures.

The model allows for a light gravitino as dark matter.

R-parity violation can be significant without conflicting with proton decay constraints.

Abstract

Supersymmetric (SUSY) models with R-parity generically predict sparticle decays with invisible neutralinos, which yield distinctive missing energy events at colliders. Since most LHC searches are designed with this expectation, the putative bounds on sparticle masses become considerably weaker if R-parity is violated so that squarks and gluinos decay to jets with large QCD backgrounds. Here we introduce a scenario in which baryonic R-parity violation (RPV) arises effectively from soft SUSY-breaking interactions, but leptonic RPV remains accidentally forbidden to evade constraints from proton decay and FCNCs. The model features a global R-symmetry that initially forbids RPV interactions, a hidden R-breaking sector, and a heavy mediator that communicates this breaking to the visible sector. After R-symmetry breaking, the mediator is integrated out and an effective RPV A-term arises at tree level; RPV couplings between quarks and squarks arise only at loop level and receive additional suppression. Although this mediator must be heavy compared to soft masses, the model introduces no new hierarchy since viable RPV can arise when the mediator mass is near the SUSY breaking scale. In generic regions of parameter space, a light thermally-produced gravitino is stable and can be a viable dark matter candidate.