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Evidence for the associated production of the Higgs boson and a top quark pair with the ATLAS detector

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journal contribution
posted on 2023-06-09, 13:28 authored by Benedict AllbrookeBenedict Allbrooke, Lily AsquithLily Asquith, Alessandro CerriAlessandro Cerri, C A Chavez Barajas, Antonella De SantoAntonella De Santo, Fabrizio SalvatoreFabrizio Salvatore, I Santoyo Castillo, K Suruliz, Mark SuttonMark Sutton, Iacopo Vivarelli, The ATLAS Collaboration
A search for the associated production of the Higgs boson with a top quark pair (t¯tH) is reported. The search is performed in multilepton final states using a data set corresponding to an integrated luminosity of 36.1 fb-1 of proton-proton collision data recorded by the ATLAS experiment at a center-of-mass energy vs=13 TeV at the Large Hadron Collider. Higgs boson decays to WW*, tt, and ZZ* are targeted. Seven final states, categorized by the number and flavor of charged-lepton candidates, are examined for the presence of the Standard Model Higgs boson with a mass of 125 GeV and a pair of top quarks. An excess of events over the expected background from Standard Model processes is found with an observed significance of 4.1 standard deviations, compared to an expectation of 2.8 standard deviations. The best fit for the t¯tH production cross section is s(t¯tH)=790 +230 -210 fb, in agreement with the Standard Model prediction of 507 +35-50 fb. The combination of this result with other t¯tH searches from the ATLAS experiment using the Higgs boson decay modes to b¯b, ?? and ZZ* ? 4l, has an observed significance of 4.2 standard deviations, compared to an expectation of 3.8 standard deviations. This provides evidence for the t¯tH production mode.

Funding

ATLAS; G0275; STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCIL; ST/I006048/1

History

Publication status

  • Published

File Version

  • Published version

Journal

Physical Review D

ISSN

2470-0010 https://doi.org/10.1103/PhysRevD.97.072003

Publisher

American Physical Society

Issue

7

Volume

97

Page range

072003

Department affiliated with

  • Physics and Astronomy Publications

Research groups affiliated with

  • Experimental Particle Physics Research Group Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2018-05-25

First Open Access (FOA) Date

2018-05-25

First Compliant Deposit (FCD) Date

2018-05-24

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