Spot the stop with a b-tag

TL;DR

This paper proposes a new monojet-like search strategy with b-tagging to effectively constrain light stop squarks decaying via a four-body mode, covering previously unconstrained mass regions using existing LHC data.

Contribution

It introduces an optimized search method for light stops decaying to a neutralino, bottom quark, and fermions, extending current exclusion limits with existing data.

Findings

The new search covers the entire unconstrained stop-neutralino mass region (90-140 GeV).

Existing 8 TeV LHC data can exclude stop masses below 100 GeV with the proposed method.

Validation against ATLAS data confirms the effectiveness of the approach.

Abstract

The LHC searches for light compressed stop squarks have resulted in considerable bounds in the case where the stop decays to a neutralino and a charm quark. However, in the case where the stop decays to a neutralino, a bottom quark and two fermions via an off-shell W-boson, there is currently a significant unconstrained region in the stop-neutralino mass plane, still allowing for stop masses in the range 90-140 GeV. In this paper we propose a new monojet-like search for light stops, optimized for the four-body decay mode, in which at least one $b$-tagged jet is required. We show that, already by using the existing 8 TeV LHC data set, such a search would cover the entire unconstrained region. Moreover, in the process of validating our tools against an ATLAS monojet search, we show that the existing limit can be extended to exclude also stop masses below 100 GeV.