Search for $W' \rightarrow tb$ decays in the hadronic final state 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, employing jet substructure techniques, and sets exclusion limits on their masses based on the non-observation of signals.

Contribution

First search to analyze $W'$ bosons decaying to $tb$ in hadronic final states at 13 TeV with advanced jet tagging, setting new mass exclusion limits.

Findings

No significant excess observed over Standard Model predictions.

Excluded $W'$ bosons with right-handed couplings below 3.0 TeV.

Excluded $W'$ bosons with left-handed couplings below 2.9 TeV.

Abstract

A search for $W'$-boson production in the $W' \rightarrow t\bar{b} \rightarrow q\bar{q}' b\bar{b}$ decay channel is presented using 36.1 fb$^{-1}$ of 13 TeV proton-proton collision data collected by the ATLAS detector at the Large Hadron Collider in 2015 and 2016. The search is interpreted in terms of both a left-handed and a right-handed chiral $W'$ boson within the mass range 1-5 TeV. Identification of the hadronically decaying top quark is performed using jet substructure tagging techniques based on a shower deconstruction algorithm. No significant deviation from the Standard Model prediction is observed and the results are expressed as upper limits on the $W' \rightarrow t\bar{b}$ production cross-section times branching ratio as a function of the $W'$-boson mass. These limits exclude $W'$ bosons with right-handed couplings with masses below 3.0 TeV and $W'$ bosons with left-handed couplings with masses below 2.9 TeV, at the 95% confidence level.