Searching for stop LSP at the LHC

TL;DR

This paper investigates signals of a stop as the lightest supersymmetric particle at the LHC within the $ u$SSM framework, focusing on displaced vertex decays and comparing predictions with experimental searches.

Contribution

It provides a comprehensive analysis of stop LSP signatures in the $ u$SSM, incorporating neutrino and Higgs data, and sets new lower mass limits based on LHC search comparisons.

Findings

Lower stop LSP mass limit of 1068 GeV for left stop

Lower stop LSP mass limit of 1341 GeV for right stop

Decay lengths of 1.86 mm and 6.61 mm respectively

Abstract

We analyze relevant signals expected at the LHC for a stop as the lightest supersymmetric particle (LSP). The discussion is carried out in the framework of the $\mu\nu$SSM, where the presence of $R$-parity violating couplings involving right-handed neutrinos solves the $\mu$-problem and reproduces neutrino data. The stops are pair produced at the LHC, decaying with displaced vertices to a lepton and a bottom quark or a neutrino and a top quark. We compare the predictions of this scenario with ATLAS and CMS searches for long-lived particles. To analyze the parameter space we sample the $\mu\nu$SSM for a stop LSP using a likelihood data-driven method, and paying special attention to reproduce the current experimental data on neutrino and Higgs physics, as well as flavor observables. Our results translate into a lower limit on the mass of the left (right) stop LSP of 1068 GeV (1341 GeV), corresponding to a decay length of 1.86 mm (6.61 mm).