Measurements of WH and ZH production in the H → b¯b decay channel in pp collisions at 13 TeV with the ATLAS detector

Abstract

Measurements of the Standard Model Higgs boson decaying into a b¯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. Themeasurements use collisions produced by the Large Hadron Collider at a centre-ofmass energy of √ s = 13 TeV, corresponding to an integrated luminosity of 139 fb−1. The production of a Higgs boson in association with aW 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 theWH and ZH processes as well as the Higgs boson decay into b¯b.