| ATLAS Note | |
| Report number | ATLAS-CONF-2019-004 |
| Title | Measurement of Higgs boson production in association with a $t\overline t$ pair in the diphoton decay channel using 139~fb$^{-1}$ of LHC data collected at $\sqrt{s} = 13$~TeV by the ATLAS experiment |
| Corporate Author(s) | The ATLAS collaboration |
| Collaboration | ATLAS Collaboration |
| Publication | 2019 |
| Imprint | 19 Mar 2019 |
| Number of pages | mult. |
| Note | All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/CONFNOTES/ATLAS-CONF-2019-004 |
| In: | 54th Rencontres de Moriond on Electroweak Interactions and Unified Theories, La Thuile, Italy, 16 - 23 Mar 2019 |
| Subject category | Particle Physics - Experiment |
| Accelerator/Facility, Experiment | CERN LHC ; ATLAS |
| Free keywords | 13 TeV ; Photons ; b-jets ; Di-photon ; Diphoton ; Top pair ; HiggsCross-section measurement ; Higgs to 2 photons ; ttH production ; H(125) measurements ; Coupling measurements ; Higgs Couplings |
| Abstract | The measurement of Higgs boson production in association with a top quark-antiquark pair in the diphoton decay channel ($H \to \gamma \gamma$) is presented, based on the analysis of 139 fb$^{-1}$ of proton-proton collision data with center-of-mass energy $\sqrt{s}=13$ TeV recorded with the ATLAS detector at the Large Hadron Collider. The analysis is performed using a simultaneous fit in seven signal-enriched event categories. The $t\bar{t}H$ process is observed in the diphoton decay mode with a significance of 4.9 standard deviations relative to the background-only hypothesis. The expected significance is 4.2 standard deviations. The $t\bar{t}H$ cross-section times the $H \to \gamma \gamma$ branching ratio is measured to be $\sigma_{t\bar{t}H}\times B_{\gamma\gamma} = 1.59_{-0.39}^{+0.43}$ fb, in agreement with the Standard Model prediction. |
Corresponding record in: Inspire
Record created 2019-03-19, last modified 2021-04-18
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