Search for single production of vector-like top partner T → H+b and H±→tb¯ at the LHC Run-III

While experimental data has not ruled out the possibility of additional Higgs bosons or gauge sectors, several alternative models have been proposed to go beyond the standard model and tackle the question of hierarchy. These models predict the existence of heavy vector-like partner quarks that exhibit vector-axial (V-A) coupling, typically on the TeV scale. In this work, we use simplified interactions to establish the fundamental components of the model and explore potential scenarios beyond the standard model. We focus on the unusual decays of the partner heavy quark, called T, into H±b, which may compete with W±b decays and create a new discovery channel at the Large Hadron Collider (LHC). Using Monte Carlo (MC) simulations, we analyze the signal-to-noise ratio of pp→qg→T+bb¯j→H+bb¯j→W+bb¯j→1ℓ+4b+1j+E̸T, and evaluate the sensitivity of the LHC to the masses of T and H± in the two-Higgs-doublet model (2HDM) plus the vector-like quark (VLQ) model with a branching ratio of 100% for T→H±b. We take into account current and predicted luminosities, as well as theoretical and experimental bounds. This paper presents a new strategy for identifying VLQs at the LHC, which goes beyond the usual search strategies that rely on decays of T into Standard Model bosons.