Exploring compressed supersymmetry with same-sign top quarks at the Large Hadron Collider

TL;DR

This paper investigates how same-sign top-quark events at the LHC can reveal properties of compressed supersymmetry models, focusing on decay signatures and mass constraints.

Contribution

It introduces a method to analyze LHC signals from gluino and squark decays in compressed SUSY, providing new ways to estimate superpartner masses.

Findings

Heavy-flavor jet counts confirm decay origins.

Transverse momentum sums estimate superpartner masses.

Invariant mass endpoints constrain gluino and top-squark masses.

Abstract

In compressed supersymmetry, a light top squark naturally mediates efficient neutralino pair annihilation to govern the thermal relic abundance of dark matter. I study the LHC signal of same-sign leptonic top-quark decays from gluino and squark production, which follows from gluino decays to top plus stop followed by the stop decaying to a charm quark and the LSP in these models. Measurements of the numbers of jets with heavy-flavor tags in the same-sign lepton events can be used to confirm the origin of the signal. Summed transverse momentum observables provide an estimate of an effective superpartner mass, which is correlated with the gluino mass. Measurements of invariant mass endpoints from the visible products of gluino decays do not allow direct determination of superpartner masses, but can place constraints on them, including lower bounds on the gluino mass as a function of the top-squark mass.