Please use this identifier to cite or link to this item:
https://hdl.handle.net/20.500.11851/12564
Title: | Search for tt¯H/A→tt¯tt¯ Production in Proton–proton Collisions at s=13 TeV With the ATLAS Detector | Authors: | Zwalinski, L. Zou, W. Zormpa, O. Zorbas, T.G. Zoch, K. Zoccoli, A. Monzani, S. |
Publisher: | Springer Nature | Abstract: | 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 top-quark 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 139fb-1. Events are selected requiring exactly one or two opposite-charge electrons or muons. Data-driven 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, tanβ 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. © The Author(s) 2025. | URI: | https://doi.org/10.1140/epjc/s10052-025-14041-z https://hdl.handle.net/20.500.11851/12564 |
ISSN: | 1434-6044 |
Appears in Collections: | Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection |
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