Speaker
Description
Four top-quark production, a rare process in the Standard Model (SM) with a cross-section around 12 fb, is one of the heaviest final states produced at the LHC, and it is naturally sensitive to physics beyond the Standard Model (BSM). The central value of the cross section measured by ATLAS is twice as large as the SM prediction (albeit with large uncertainties). A follow-up analysis is the search for Heavy (pseudo)Higgs boson A/H produced in association with a top-antitop quark pair leading to the final state with four top quarks. The data analyzed correspond to an integrated luminosity of 139 fb$^{-1}$. In this poster, the four top-quark decay final states containing either a pair of same-sign leptons or multi-lepton (SSML) are considered. To enhance the search sensitivity, a mass-parameterized BDT is introduced to discriminate the BSM signal against the irreducible SM four-top and other dominant SM backgrounds. Observed and expected upper bounds on the production cross-section of A/H are derived in the mass range from 400 GeV to 1000 GeV.
| In-person participation | Yes |
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