Электронный каталог

Статья

Aad, G.
Search for tt^-H/A *> tt^-tt^- Production in Proton-Proton Collisions at *%s=13 TeV with the ATLAS Detector / G.Aad, F.Ahmadov, I.N.Aleksandrov, V.A.Bednyakov, I.R.Boyko, G.Chelkov, A.Cheplakov, M.V.Chizhov, D.V.Dedovich, M.Demichev, M.I.Gostkin, S.N.Karpov, Z.M.Karpova, U.Kruchonak, V.Kukhtin, E.Ladygin, V.Lyubushkin, T.Lyubushkina, S.Malyukov, M.Mineev, E.Plotnikova, I.N.Potrap, N.A.Rusakovich, M.Shiyakova, A.Soloshenko, T.Turtuvshin, A.Vasyukov, I.Yeletskikh, A.Zhemchugov, N.I.Zimine, Y.Kulchitsky, [ATLAS Collab.]. – Text : electronic // The European Physical Journal C. – 2025. – Vol. 85, No. 5. – P. 573. – URL: https://doi.org/10.1140/epjc/s10052-025-14041-z. – Bibliogr.: 121.

A search is presented for a heavy scalar (H) or pseudo-scalar (A) predicted by the two-Higgs-doublet models, where the H/A is produced in association with a topquark pair(tt^-H /A), and with the H/A decaying into a tt^- pair. The full LHC Run 2 proton–proton collision data collected by the ATLAS experiment is used, corresponding to an integrated luminosity of 139 fb&sup(−1). Events are selected requiring exactly one or two opposite-charge electrons or muons. Datadriven corrections are applied to improve the modelling of the tt^-+jets background in the regime with high jet and b-jet multiplicities. These include a novel multi-dimensional kinematic reweighting based on a neural network trained using data and simulations. An H/A-mass parameterised graph neural network is trained to optimise the signal-to-background discrimination. In combination with the previous search performed by the ATLAS Collaboration in the multilepton final state, the observed upper limits on the tt^-H/A → tt^-tt^-production cross-section at 95% confidence level range between 14 fb and 5.0 fb for an H/A with mass between 400 GeV and 1000 GeV, respectively. Assuming that both the H and A contribute to the tt^-tt^-cross-section, tan β values below 1.7 or 0.7 are excluded for a mass of 400 GeV or 1000 GeV, respectively. The results are also used to constrain a model predicting the pair production of a colour-octet scalar, with the scalar decaying into a tt^- pair.



ОИЯИ = ОИЯИ (JINR)2025
Спец.(статьи,препринты) = С 346.2в - Взаимодействие протонов с протонами
Спец.(статьи,препринты) = С 346.6д1 - Чармоний, боттомоний, топ-кварк. Очарованные частицы и др. резонансы из тяжелых кварков