Supersymmetry with long-lived staus at the LHC

TL;DR

This paper explores supersymmetric models with long-lived staus at the LHC, highlighting how their detection differs from standard models and analyzing current bounds and strategies for observation.

Contribution

It introduces a scenario with long-lived staus that mimic muons, analyzing its unique collider signatures and how current searches constrain this model.

Findings

Long-lived staus can be mistaken for muons in collider detectors.

This scenario predicts more leptons and a strong e-mu asymmetry.

Current LHC analyses place bounds on this SUSY scenario.

Abstract

We consider SUSY extensions of the standard model where the gravitino is the dark-matter particle and the stau is long lived. If there is a significant mass gap with squarks and gluinos, the staus produced at hadron colliders tend to be fast (beta>0.8), and the searches based on their delay in the time of flight or their anomalous ionization become less effective. Such staus would be identified as regular muons with the same linear momentum and a slightly reduced energy. Compared to the usual SUSY models where a neutralino is the LSP, this scenario implies (i) more leptons (the two staus at the end of the decay chains), (ii) a strong e-mu asymmetry, and (iii) less missing E_T (just from neutrinos, as the lightest neutralino decays into stau). We study the bounds on this SUSY from current LHC analyses (same-sign dileptons and multilepton events) and discuss the best strategy for its observation.