Search for single vector-like quark production in opposite-sign dilepton final states in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports a search for single vector-like top quark production decaying into a top quark and Higgs boson in dilepton final states at 13 TeV, setting upper limits on production cross sections.

Contribution

First search in the T → tH channel with opposite-sign dilepton final states at the LHC, providing new constraints on vector-like quark models.

Findings

No excess observed over background expectations.

Upper limits on cross section times branching ratio range from 2.0 pb to 0.1 pb for T masses 600-1000 GeV.

First analysis of this decay channel in dilepton final states.

Abstract

A search is presented for single production of a vector-like top quark T, decaying into the standard model top quark and Higgs boson, in a final state including two opposite-sign leptons (electrons or muons), jets, and missing transverse momentum. The data were recorded by the CMS experiment in proton-proton collisions at a center-of-mass energy of 13 TeV at the CERN LHC in the years 2016$-$2018, and corresponding to an integrated luminosity of up to 138 fb$^{-1}$. No excess in data over the background expectations is observed. Upper limits at 95% confidence level on the product of the T production cross section and its decay branching fraction to tH are set, ranging from 2.0 pb at a T mass of 600 GeV to 0.1 pb at 1000 GeV. This is the first search in the T $\to$ tH channel in opposite-sign dilepton final states.