Light Stop Searches at the LHC in Events with two b-Jets and Missing Energy

TL;DR

This paper introduces a new method for detecting light top squarks at the LHC in events with two b-jets and missing energy, focusing on scenarios compatible with dark matter and baryogenesis.

Contribution

It presents a novel search strategy considering electroweak and QCD contributions for light stops decaying into charm quarks and neutralinos, expanding detection possibilities.

Findings

Electroweak contributions can surpass pure QCD in stop production.

The proposed method enhances LHC discovery potential for specific supersymmetric scenarios.

The analysis maps the discovery reach in the stop-neutralino mass parameter space.

Abstract

We propose a new method to discover light top squarks (stops) in the co-annihilation region at the Large Hadron Collider (LHC). The bino-like neutralino is the lightest supersymmetric particle (LSP) and the lighter stop is the next-to-LSP. Such scenarios can be consistent with electroweak baryogenesis and also with dark matter constraints. We consider the production of two stops in association with two b-quarks, including pure QCD as well as mixed electroweak-QCD contributions. The stops decay into a charm quark and the LSP. For a higgsino-like light chargino the electroweak contributions can exceed the pure QCD prediction. We show the size of the electroweak contributions as a function of the stop mass and present the LHC discovery reach in the stop-neutralino mass plane.