Measurements of $W^+W^-+\ge 1~$jet production cross-sections in $pp$ collisions at $\sqrt{s}=13~$TeV with the ATLAS detector

TL;DR

This paper reports precise measurements of $W^+W^-$ production with at least one jet at 13 TeV, testing electroweak and QCD theories and setting limits on anomalous gauge couplings using ATLAS data.

Contribution

First measurement of $W^+W^- + ext{jets}$ differential cross-sections at 13 TeV with detailed kinematic analysis and constraints on anomalous couplings.

Findings

Measured fiducial and differential cross-sections with high precision.

Probed new event topology at the LHC involving $W^+W^-$ with jets.

Set limits on anomalous triple-gauge-boson couplings.

Abstract

Fiducial and differential measurements of $W^+W^-$ production in events with at least one hadronic jet are presented. These cross-section measurements are sensitive to the properties of electroweak-boson self-interactions and provide a test of perturbative quantum chromodynamics and the electroweak theory. The analysis is performed using proton$-$proton collision data collected at $\sqrt{s}=13~$TeV with the ATLAS experiment, corresponding to an integrated luminosity of 139$~$fb$^{-1}$. Events are selected with exactly one oppositely charged electron$-$muon pair and at least one hadronic jet with a transverse momentum of $p_{\mathrm{T}}>30~$GeV and a pseudorapidity of $|\eta|<4.5$. After subtracting the background contributions and correcting for detector effects, the jet-inclusive $W^+W^-+\ge 1~$jet fiducial cross-section and $W^+W^-+$ jets differential cross-sections with respect to several kinematic variables are measured, thus probing a previously unexplored event topology at the LHC. These measurements include leptonic quantities, such as the lepton transverse momenta and the transverse mass of the $W^+W^-$ system, as well as jet-related observables such as the leading jet transverse momentum and the jet multiplicity. Limits on anomalous triple-gauge-boson couplings are obtained in a phase space where interference between the Standard Model amplitude and the anomalous amplitude is enhanced.