A Model With Dynamical R-parity Breaking and Unstable Gravitino Dark Matter

TL;DR

This paper proposes a minimal supersymmetric left-right model where dynamical R-parity breaking leads to an unstable gravitino dark matter candidate with a long lifetime, compatible with observations and detectable at the LHC.

Contribution

It introduces a natural realization of R-parity breaking in minimal supersymmetric left-right models, connecting neutrino masses, dark matter stability, and collider phenomenology.

Findings

Gravitino can be a long-lived dark matter candidate with lifetime >10^{26} sec.

Model predicts displaced vertices at the LHC from NLSP decays.

R-parity breaking is naturally suppressed, consistent with neutrino mass constraints.

Abstract

An unstable gravitino with lifetime longer than $10^{26}$ sec or so has been proposed as a possible dark matter candidate in supergravity models with R-parity breaking. We find a natural realization of this idea in the minimal supersymmetric left-right models where left-right symmetry breaking scale in the few TeV range. It is known that in these models, R-parity must break in order to have parity breaking as required by low energy weak interactions. The sub-eV neutrino masses imply that R-parity breaking effects in this model must be highly suppressed. This in turn makes the gravitino LSP long lived enough, so that it becomes the dark matter of the Universe. It also allows detectable displaced vertices at the LHC from NLSP decays. We present a detailed analysis of the model and some aspects of its rich phenomenology.