Evidence of Higgs boson inclusive production at high transverse momentum decaying to a pair of $b$-quarks with the ATLAS detector

Abstract

This letter reports on the first evidence of Higgs-boson production at high transverse momentum in the $b\bar{b}$ 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 centre-of-mass energies of 13 TeV 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, $p_{\text{T}}$, resolution from a dedicated regression model. The yield relative to the Standard Model prediction, for Higgs bosons produced at $p_{\text{T}}$ larger than 450 GeV is measured to be $1.53\pm 0.27\text{(stat.)}\ ^{+0.33}_{-0.27}\text{(syst.)}\pm 0.17\text{(theo.)}$ corresponding to an observed (expected) significance of $3.8σ(2.5σ)$ relative to the background-only hypothesis. Results are also obtained in three Higgs boson $p_{\text{T}}$ intervals and found to be compatible with Standard Model predictions.

Figures (3)

• Figure 1: Observed $\PZ \rightarrow \Pgm{}\Pgm\xspace\text{+\,jet(s)}$ event rate as a function of jet $p_{\text{T}}$ compared to theoretical predictions from Sherpa 2.2.14 including QCD NNLO corrections from NNLOJET Ridder:2015dxaRidder:2016nkl and EW NLO corrections from Sherpa with uncertainties estimates from Ref. Lindert:2017olm. The $W/Z\rightarrow\Pq{}\Paq$ and $\PZ \rightarrow \Pqb{}\Paqb$ rates, the latter uncalibrated for GN2X efficiency, are overlaid for comparison (upper panel). Fitted values of the leading and subleading $\kappa^{\mathrm{GN2X}}_{bb}$ factors averaged over datasets are shown within each $p_{\text{T}}$ bin in the lower panel.
• Figure 2: Post-fit jet mass distributions in the (a) $450<p_{\text{T}}\xspace<650~\text{Ge V}\xspace$, (b) $650<p_{\text{T}}\xspace<1000~\text{Ge V}\xspace$, and (c) $p_{\text{T}}\xspace>1000~\text{Ge V}\xspace$ signal regions, summed over jet categories and datasets. The middle panel shows the data with the multijet background subtracted, and the bottom panel shows the data with all backgrounds subtracted. The fit is performed simultaneously across the twelve signal–control region pairs, with the Higgs boson contribution scaled to the fitted $\mu_H$.
• Figure 3: Measured inclusive Higgs boson production signal strengths for the Run 2 and Run 3 datasets as a function of $p_{\mathrm{T}}^{H}$. The EW NLO corrections Denner:2014cla, averaged over the $VH$, $\text{VBF}$ and $\Pqt{}\Paqt H$ Higgs production processes, are also shown.