Constraining slepton and chargino through compressed top squark search

TL;DR

This paper explores advanced collider search strategies for compressed supersymmetric spectra involving top squarks, charginos, and sleptons, proposing new kinematic variables to improve detection sensitivity at the LHC.

Contribution

It introduces novel kinematic variables and analysis techniques to extend the search reach for compressed SUSY spectra including charginos and sleptons at the LHC.

Findings

Top squark masses up to 710 GeV can be excluded with current LHC data.

New kinematic variables improve sensitivity to compressed SUSY spectra.

The analysis extends the search for SUSY particles in challenging compressed regions.

Abstract

We examine the compressed mass spectrum with sub-TeV top squark ($\tilde t$) as lightest colored (s)particle in natural supersymmetry (SUSY). Such spectra are searched along with an additional hard jet, not only to boost the soft decay particles, also to yield enough missing transverse momentum. Several interesting kinematic variables are proposed to improve the probe performance for this difficult region, where we concentrate on relatively clean dileptonic channel of the top squark decaying into lightest neutralino ($\chi_1^0$), which is also the lightest supersymmetric particle. In this work, we investigate the merit of these kinematic variables, sensitive to compressed mass region extending the search by introducing additional states, chargino and slepton (sneutrino) having masses in between the $\tilde t$ and $\chi_1^0$. Enhanced production and lack of branching suppression are capable of providing a strong limit on chargino and slepton/sneutrino mass along with top squark mass. We perform a detailed collider analysis using simplified SUSY spectrum and found that with the present LHC data $M_{\tilde t}$ can be excluded up to 710 GeV right away for $M_{\chi_1^0}$ of 640 GeV for a particular mass gap between different states.