Search for vector-boson resonances decaying into a top quark and a bottom quark using $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

TL;DR

This paper reports a search for new heavy $W'$ bosons decaying into top and bottom quarks using 13 TeV proton-proton collision data from the ATLAS detector, setting limits on their production and properties.

Contribution

First search to analyze $W'$ bosons decaying into $tb$ with various chiralities and couplings at 13 TeV, providing new constraints on their existence.

Findings

No significant excess observed over background.

Upper limits set on $W'$ production cross-section and coupling parameters.

Mass range explored from 0.5 to 6 TeV.

Abstract

A search for a new massive charged gauge boson, $W'$, is performed with the ATLAS detector at the LHC. The dataset used in this analysis was collected from proton-proton collisions at a centre-of-mass energy of $\sqrt{s} =13$ TeV, and corresponds to an integrated luminosity of 139 fb$^{-1}$. The reconstructed $tb$ invariant mass is used to search for a $W'$ boson decaying into a top quark and a bottom quark. The result is interpreted in terms of a $W'$ boson with purely right-handed or left-handed chirality in a mass range of 0.5-6 TeV. Different values for the coupling of the $W'$ boson to the top and bottom quarks are considered, taking into account interference with single-top-quark production in the $s$-channel. No significant deviation from the background prediction is observed. The results are expressed as upper limits on the $W' \rightarrow tb$ production cross-section times branching ratio as a function of the $W'$-boson mass and in the plane of the coupling vs the $W'$-boson mass.