Light Stop NLSPs at the Tevatron and LHC

TL;DR

This paper investigates the potential for very light stop particles in supersymmetry models to evade current collider constraints, highlighting the importance of dedicated searches at the Tevatron and LHC.

Contribution

It provides the first detailed simulation of existing collider analyses' sensitivity to light stop NLSPs in gauge-mediated supersymmetry breaking models.

Findings

Stops as light as 150 GeV are still allowed by current data.

Future LHC analyses could exclude stops up to 180 GeV with more data.

Large top background complicates the detection of light stops.

Abstract

How light can the stop be given current experimental constraints? Can it still be lighter than the top? In this paper, we study this and related questions in the context of gauge-mediated supersymmetry breaking, where a stop NLSP decays into a W, b and gravitino. Focusing on the case of prompt decays, we simulate several existing Tevatron and LHC analyses that would be sensitive to this scenario, and find that they allow the stop to be as light as 150 GeV, mostly due to the large top production background. With more data, the existing LHC analyses will be able to push the limit up to at least 180 GeV. We hope this work will motivate more dedicated experimental searches for this simple scenario, in which, for most purposes, the only free parameters are the stop mass and lifetime.