Measurements of <it>WH</it> and <it>ZH</it> production in the H -> bb<mml:mo stretchy=false><overbar></mml:mover> decay channel in <it>pp</it> collisions at 13<mml:mspace width=0.166667em></mml:mspace>Te<mml:mspace width=0.333333em></mml:mspace> with the ATLAS detector

Abstract

Measurements of the Standard Model Higgs boson decaying into a bb<overbar></mml:mover> 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 <mml:msqrt>s</mml:msqrt>=13<mml:mspace width=0.166667em></mml:mspace>Te<mml:mspace width=0.333333em></mml:mspace>, corresponding to an integrated luminosity of 139<mml:mspace width=0.166667em></mml:mspace>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<mml:mover accent=true>b<mml:mo stretchy=false><overbar></mml:mover>.