Probing vector-like top partner from same-sign dilepton events at the LHC

Abstract

The Standard Model is a successful theory but lack of a mechanism for neutrino mass generation as well as a solution to the naturalness problem. In the models that are proposed to simultaneously solve the two problems, heavy Majorana neutrinos and top partners are usually predicted that can lead to a new decay mode of the top partner mediated by the heavy Majorana neutrinos: $T\to b{W}^{+}\to b{\ell }^{+}{\ell }^{+}q\overline{q^{\prime }}$. In this paper, we will study the observability of such a new signature via the pair production process of top partner $pp\to T\bar{T}\to 2b+{\ell }^{\pm }{\ell }^{\pm }+4j$ in a model independent way. By performing Monte-Carlo simulation, we present the $2\sigma$ exclusion limits of the top partner mass and mixing parameters at the HL-LHC.

Comments: 17 pages, 5 figures, 1 table; Discussion added; Version accepted by Communications in Theoretical Physics