Measurement of the associated production of a top-antitop-quark pair and a Higgs boson decaying into a $b\bar{b}$ pair in $pp$ collisions at $\sqrt{s}=13$ TeV using the ATLAS detector at the LHC

TL;DR

This paper measures the production rate of a Higgs boson with a top-antitop pair in proton-proton collisions at 13 TeV, finding results consistent with the Standard Model and providing differential cross-section measurements.

Contribution

It presents the first measurement of the $t\bar{t}H$ production cross-section in the $b\bar{b}$ decay channel at 13 TeV with detailed differential analysis.

Findings

Observed significance of 4.6 standard deviations.

Measured cross-section of 411 ± 54 (stat.) ± 85 (syst.) fb.

Results are consistent with Standard Model predictions.

Abstract

This paper reports the measurement of Higgs boson production in association with a $t\bar{t}$ pair in the $H \rightarrow b \bar{b}$ decay channel. The analysis uses 140 fb$^{-1}$ of 13 TeV proton-proton collision data collected with the ATLAS detector at the Large Hadron Collider. The final states with one or two electrons or muons are employed. An excess of events over the expected background is found with an observed (expected) significance of 4.6 (5.4) standard deviations. The $t \bar{t} H$ cross-section is $\sigma_{t \bar tH} = 411^{+101}_{-92} \text{fb} = 411 \pm 54(\text{stat.}) ^{+85}_{-75}(\text{syst.})$ $\text{fb}$ for a Higgs boson mass of 125.09 GeV, consistent with the prediction of the Standard Model of $507^{+35}_{-50}$ $\text{fb}$. The cross-section is also measured differentially in bins of the Higgs boson transverse momentum within the simplified template cross-section framework.