Light Gravitinos at Colliders and Implications for Cosmology

TL;DR

This paper explores how collider experiments can detect light gravitinos, providing insights into their role as dark matter and their implications for early-Universe cosmology.

Contribution

It demonstrates that collider data can identify light gravitinos and differentiate between scenarios, impacting our understanding of cosmology and structure formation.

Findings

Tevatron and LHC can observe hundreds of light-gravitino events

Collider signals include di-photons and metastable charged particles

Data can distinguish between different light-gravitino models

Abstract

Light gravitinos, with mass in the eV to MeV range, are well-motivated in particle physics, but their status as dark-matter candidates is muddled by early-Universe uncertainties. We investigate how upcoming data from colliders may clarify this picture. Light gravitinos are produced primarily in the decays of the next-to-lightest supersymmetric particle, resulting in spectacular signals, including di-photons, delayed and non-pointing photons, kinked charged tracks, and heavy metastable charged particles. We find that the Tevatron with 20/fb and the 7 TeV LHC with 1/fb may both see evidence for hundreds of light-gravitino events. Remarkably, this collider data is also well suited to distinguish between currently viable light-gravitino scenarios, with striking implications for structure formation, inflation, and other early-Universe cosmology.