Measurement of the associated production of a higgs boson decaying into b-quarks with a vector boson at high transverse momentum with the atlas detector

Abstract

The observation of the decay of the Higgs boson to a bb pair in 2018 provided a confirmation of the Yukawa interaction and the first measurement of a Yukawa coupling to down-type quarks. The experimental challenges that the H → bb decay entails at hadron colliders can be addressed by studying the associated Higgs boson production with a vector boson V decaying leptonically. Following the observation, the main focus is now the study of the Higgs boson production cross section as a function of its transverse momentum (pT). These measurements are well motivated by a wide range of Beyond the Standard Model (BSM) theories predicting an enhancement of V H(H → bb) events at high transverse momentum with respect to the SM expectations. At such high energy regimes, the Higgs boson is highly Lorentz-boosted and the H → bb decay is reconstructed in the detector as a single object with a two-prong substructure, using novel techniques. The paper will illustrate the measurement of V H(H → bb) in the boosted regime performed inclusively, as well as in bins of the vector boson transverse momentum, for pVTϵ [250; 400) GeV and pVTϵ [400;∞) GeV. Their interpretation using the Effective Field Theory (EFT) framework will also be discussed. The results are based on the full LHC Run 2 dataset collected by the ATLAS experiment, corresponding to an integrated luminosity of 139 fb-1