Evidence of Higgs Boson Inclusive Production at High Transverse Momentum Decaying to a Pair of b-Quarks with the ATLAS Detector

This Letter reports on the first evidence of inclusive Higgs-boson production at high transverse momentum in the b bbar final state, reconstructed in a single large-radius jet. The results are based on proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider at a center-of-mass energies of 13 and 13.6 TeV, corresponding to a total integrated luminosity of 301  fb^{-1}. The study profits from the large background suppression provided by the use of a new transformer-based algorithm for jet identification and the sharper mass and transverse momentum, p_{T}, resolution from a dedicated regression model. The yield relative to the standard model prediction for Higgs bosons produced at p_{T} larger than 450 GeV is measured to be 1.53+-0.27)_{-0.27}^{+0.33}+-0.17, where the first uncertainty is statistical, the second is experimental systematic, and the third accounts for theory systematic, corresponding to an observed (expected) significance of 3.8 sigma (2.5 sigma) relative to the background-only hypothesis. Results are also obtained in three Higgs boson p_{T} intervals and found to be compatible with standard model predictions, where the first uncertainty is statistical, the second is experimental systematic, and the third accounts for theory systematic.