Measurement Of The Associated Production Of A Higgs Boson Decaying To B(?) With A Vector Boson At High Transverse Momentum In Pp Collisions At (?)=13 TeV With The ATLAS Detector

The Higgs boson discovered by the ATLAS and CMS Collaborations in 2012 and the dominant decay of the Stand Model(SM)Higgs boson is into pairs of b-quarks(H?bb)with an expected branching fraction of?58%,which was discovered by the ATLAS and CMS Collaborations in 2018.Since the discovery,the precise measurement of the H?precess has been started in the ATLAS and CMS experiments,of which the cross-section measurement of H?bb production in the high transverse momentum(pT)regime is an important part.In the The previous analyses in this channel,separate calorimeter jets with radius parameter of R=0.4(small-R),are used to reconstruct the Higgs boson.For higher transverse momentum,the two b-quarks decayed from Higgs boson become close enough and two jets of the two b-quarks can be merged together,causing the reconstruction efficiency decreasing.In order to improve the efficiency in the high pT regime,instead of separate small-R jets,a single large-R jet with R=1.0 is used for the Higgs boson reconstruction.The associated production of a Higgs boson with a W or Z boson decaying to leptons and where the Higgs boson decays to a bb pair is measured in the high pT re-gime with the ATLAS detector.The analysed data,corresponding to an integrated lu-minosity of 139 fb-1,were collected in proton-proton collisions at Run-2 of the Large Hadron Collider(LHC)at a centre-of-mass energy of(?)=13TeV.The events are separated into three individual channels depended on the decay of the vector boson:0-lepton(Z?vv),1-lepton(W?lv)and 2-lepton(Z?ll)channels(e?el?).The Higgs boson is reconstructed as a single large-R jet and track jets are used to tag the b-quarks from its decay.Ther ratio of the measured event yield for H?bb to the Standard Model expectation is 0.72-0.36+0.39=0.72-0.28+0.29(Stat.)-0.22+0.26(Syst.),correspond-ing to an observed(expected)significance of 2.1?(2.7?).Cross-sections are measured in two ranges of gauge boson PT,250-400 GeV and above 400 GeV,according to fiducial region definitions of the simplified template cross-section(STXS)framework.The cross-section of WZ/ZZ,Z?bb production is measured as a validation of the analysis stragtegy.Ther ratio of the measured event yield for Z?bb to the Stand-ard Model expectation is 0.92-0.23+0.29=0.92-0.15+0.15(Stat.)-0.17+0.25(Syst.),corresponding to an observed(expected)significance of 5.4?(5.7?).