Observation of $\mathrm{t\overline{t}}$H production

TL;DR

This paper reports the first observation of Higgs boson production with a top quark-antiquark pair, using combined data from the CMS detector at CERN, achieving a significance of 5.2 standard deviations.

Contribution

It provides the first experimental evidence of the Higgs boson produced in association with top quarks, confirming a key Standard Model prediction.

Findings

Significance of 5.2 standard deviations for t-tbar-H production

Measured signal strength of 1.26 times the Standard Model prediction

Combined analysis of multiple decay channels enhances sensitivity

Abstract

The observation of Higgs boson production in association with a top quark-antiquark pair is reported, based on a combined analysis of proton-proton collision data at center-of-mass energies of $\sqrt{s}=$ 7, 8, and 13 TeV, corresponding to integrated luminosities of up to 5.1, 19.7, and 35.9 fb$^{-1}$, respectively. The data were collected with the CMS detector at the CERN LHC. The results of statistically independent searches for Higgs bosons produced in conjunction with a top quark-antiquark pair and decaying to pairs of W bosons, Z bosons, photons, $\tau$ leptons, or bottom quark jets are combined to maximize sensitivity. An excess of events is observed, with a significance of 5.2 standard deviations, over the expectation from the background-only hypothesis. The corresponding expected significance from the standard model for a Higgs boson mass of 125.09 GeV is 4.2 standard deviations. The combined best fit signal strength normalized to the standard model prediction is 1.26 ${^{+0.31}_{-0.26}}$.