Search for W' bosons decaying to a top and a bottom quark at $\sqrt{s} =$ 13 TeV in the hadronic final state

TL;DR

This paper reports a search for W' bosons decaying into top and bottom quarks in proton-proton collisions at 13 TeV, using deep neural networks for jet identification, setting new exclusion limits up to 3.4 TeV.

Contribution

It introduces the first application of deep neural networks to identify decay jets in a W' boson search in the all-hadronic final state at 13 TeV.

Findings

No W' boson signal observed.

Excluded W' bosons with masses below 3.4 TeV.

Set the most stringent limits to date on this decay channel.

Abstract

A search is performed for W' bosons decaying to a top and a bottom quark in the all-hadronic final state, in proton-proton collisions at a center-of-mass energy of 13 TeV. The analyzed data were collected by the CMS experiment between 2016 and 2018 and correspond to an integrated luminosity of 137 fb$^{-1}$. Deep neural network algorithms are used to identify the jet initiated by the bottom quark and the jet containing the decay products of the top quark when the W boson from the top quark decays hadronically. No excess above the estimated standard model background is observed. Upper limits on the production cross sections of W' bosons decaying to a top and a bottom quark are set. Both left- and right-handed W' bosons with masses below 3.4 TeV are excluded at 95% confidence level, and the most stringent limits to date on W' bosons decaying to a top and a bottom quark in the all-hadronic final state are obtained.