Light gravitino dark matter: LHC searches and Hubble tension

TL;DR

This paper explores keV gravitino dark matter with a non-thermal component, examining its testability at the LHC and its potential to alleviate the Hubble tension, highlighting a highly predictive scenario beyond standard cosmology.

Contribution

It introduces a novel scenario of keV gravitino dark matter with a non-thermal component and discusses its implications for collider searches and the Hubble tension.

Findings

Testable via dilepton plus missing energy events at the LHC

Can marginally reduce the Hubble tension to 3σ

Highly predictive scenario constrained by cosmological data

Abstract

The recent measurements of the cosmological parameter $H_0$ from the direct local observations and the inferred value from the Cosmic Microwave Background show $\sim 4 \sigma$ discrepancy. This may indicate new physics beyond the standard $\Lambda$CDM. We investigate the keV gravitino dark matter that has a small fraction of non-thermal component (e.g. from the late decay of NLSP bino) under various cosmological constraints. We find such a scenario is highly predictive and can be tested by searching for the dilepton plus missing energy events at the LHC. Besides, we also discuss its implication for Hubble tension, however, which can be reduced to $3\sigma$ level marginally.