Measurements of $WH$ and $ZH$ production in the $H \rightarrow b\bar{b}$ decay channel in $pp$ collisions at 13 TeV with the ATLAS detector

TL;DR

This paper reports precise measurements of Higgs boson production in association with W and Z bosons decaying into leptons, using 13 TeV proton-proton collision data, confirming consistency with the Standard Model and setting limits on new physics.

Contribution

First detailed measurement of $WH$ and $ZH$ production with $H ightarrow b\bar{b}$ at 13 TeV with high luminosity, including cross-sections and limits on effective Lagrangian parameters.

Findings

Production of Higgs with W/Z bosons observed with >4 sigma significance.

Measured cross-sections align with Standard Model predictions.

Set limits on anomalous couplings affecting $WH$, $ZH$, and $H \rightarrow b\bar{b}$ processes.

Abstract

Measurements of the Standard Model Higgs boson decaying into a $b\bar{b}$ pair and produced in association with a $W$ or $Z$ boson decaying into leptons, using proton-proton collision data collected between 2015 and 2018 by the ATLAS detector, are presented. The measurements use collisions produced by the Large Hadron Collider at a centre-of-mass energy of $\sqrt{s} = $13 TeV, corresponding to an integrated luminosity of 139 fb$^{-1}$. The production of a Higgs boson in association with a $W$ or $Z$ boson is established with observed (expected) significances of 4.0 (4.1) and 5.3 (5.1) standard deviations, respectively. Cross-sections of associated production of a Higgs boson decaying into bottom quark pairs with an electroweak gauge boson, $W$ or $Z$, decaying into leptons are measured as a function of the gauge boson transverse momentum in kinematic fiducial volumes. The cross-section measurements are all consistent with the Standard Model expectations, and the total uncertainties vary from 30% in the high gauge boson transverse momentum regions to 85% in the low regions. Limits are subsequently set on the parameters of an effective Lagrangian sensitive to modifications of the $WH$ and $ZH$ processes as well as the Higgs boson decay into $b\bar{b}$.