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

The observation of the decay of the Higgs boson to a $b \bar{b}$ 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 $H \rightarrow b \bar{b}$ 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 ($p_T$). These measurements are well motivated by a wide range of Beyond the Standard Model (BSM) theories predicting an enhancement of $VH(H \rightarrow b \bar{b})$ 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 $H \rightarrow b\bar{b}$ decay is reconstructed in the detector as a single object with a two-prong substructure, using novel techniques. The talk will illustrate the measurement of $VH(H \rightarrow b \bar{b})$ in the boosted regime performed inclusively, as well as in bins of the vector boson transverse momentum, for $p_T^V \in [250,400[$ GeV and $p_T^V \in [400,\infty[$ 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$^{-1}$.