Simplified Models for Exotic BSM Searches

TL;DR

This paper extends simplified models for LHC BSM searches to include heavy stable charged particles, analyzing the CMSSM stau co-annihilation region and showing it is constrained by LHC and dark matter data.

Contribution

It introduces an extension of SModelS to incorporate HSCP signatures and applies it to the CMSSM stau co-annihilation region, combining collider and dark matter constraints.

Findings

Long-lived staus in the CMSSM are excluded or constrained by LHC and dark matter data.

The extended model can interpret exotic signatures beyond MET.

The parameter space for low tanβ is highly restricted.

Abstract

Simplified models are a successful way of interpreting current LHC searches for models beyond the standard model (BSM). So far simplified models have focused on topologies featuring a missing transverse energy (MET) signature. However, in some BSM theories other, more exotic, signatures occur. If a charged particle becomes long-lived on collider time scales - as it is the case in parts of the SUSY parameter space - it leads to a very distinct signature. We present an extension of the computer package SModelS which includes simplified models for heavy stable charged particles (HSCP). As a physical application we investigate the CMSSM stau co-annihilation strip containing long-lived staus, which presents a potential solution to the Lithium problem. Applying both MET and HSCP constraints we show that, for low values of $\tan\beta$, all this region of parameter space either violates Dark Matter constraints or is excluded by LHC searches.