Probing a new decay of vector-like top partner mediated by heavy Majorana neutrino via single production

TL;DR

This paper investigates a novel decay channel of vector-like top partners mediated by heavy Majorana neutrinos, analyzing its detectability at the 14 TeV LHC and establishing new exclusion bounds surpassing previous searches.

Contribution

It introduces a new decay mode of the top partner involving Majorana neutrinos and evaluates its observability at the LHC, providing improved exclusion limits.

Findings

Established 2σ exclusion bounds on top partner mass and mixing parameters.

Demonstrated the new decay channel's potential to surpass previous search sensitivities.

Analyzed the decay process through Monte Carlo simulations at 14 TeV LHC.

Abstract

Models beyond the Standard Model have been proposed to simultaneously solve the problems of naturalness and neutrino mass, in which heavy Majorana neutrinos and vector-like top partners are usually predicted. A new decay channel of the top partner mediated by the heavy Majorana neutrino can thus appear: $T\to b\,W^{+}\to b\,\ell^{+}\ell^{+}q\bar{q'}$. We study in this paper the observability of this decay process through single production of the top partner at the 14 TeV LHC: $pp\to T/\bar{T}$+jets$\to b/\bar{b}+\mu^{\pm}\mu^{\pm}$+jets. $2\sigma$ exclusion bounds on the top partner mass and mixing parameters are given by Monte-Carlo simulation, which surpass those from the search through VLT pair production in the mass range of $m_{T}>1.3$ TeV.