Current experimental bounds on stop mass in natural SUSY

TL;DR

This paper analyzes LHC search results to set an upper limit of 600 GeV on the stop mass in natural SUSY, considering various decay channels and experimental constraints.

Contribution

It provides a comprehensive analysis combining parameter space scans and Monte Carlo simulations to derive experimental bounds on the stop mass in natural SUSY.

Findings

Stops lighter than 600 GeV are excluded at 95% CL.

The analysis incorporates multiple decay channels and experimental data.

Constraints from Higgs mass, B-physics, and electroweak measurements are considered.

Abstract

Motivated by the recent progress of direct search for the productions of stop pair and sbottom pair at the LHC, we examine the constraints of the search results on the stop ($\tilde{t}_1$) mass in natural SUSY. We first scan the parameter space of natural SUSY in the framework of MSSM, considering the constraints from the Higgs mass, B-physics and electroweak precision measurements. Then in the allowed parameter space we perform a Monte Carlo simulation for stop pair production followed by $\tilde{t}_{1} \to t \tilde{\chi}_{1}^{0}$ or $\tilde{t}_{1} \to b \tilde{\chi}_{1}^{+}$ and sbottom pair production followed by $\tilde{b}_{1} \to b \tilde{\chi}_{1}^{0}$ or $\tilde{b}_{1} \to t \tilde{\chi}_{1}^{-}$. Using the combined results of ATLAS with 20.1 fb$^{-1}$ from the search of $\ell+{\rm jets}+\slashed E_{T}$, hadronic $t\bar{t}+\slashed E_{T}$ and $2b+\slashed E_{T}$, we find that a stop lighter than 600 GeV can be excluded at 95% CL in this scenario.