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arXiv · 2303.05974

Probing the $CP$ nature of the top-Higgs Yukawa coupling in $t\bar{t}H$ and $tH$ events with $H \to b\bar{b}$ decays using the ATLAS detector at the LHC

ATLAS Collaboration
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Abstract

The $CP$ properties of the coupling between the Higgs boson and the top quark are investigated with 139 fb$^{-1}$ of proton-proton collision data recorded by the ATLAS experiment at the LHC at a centre-of-mass energy of $\sqrt{s}=13$ TeV. The $CP$ structure of the top quark-Higgs boson Yukawa coupling is probed in events with a Higgs boson decaying into a pair of $b$-quarks and produced in association with either a pair of top quarks, $t\bar{t}H$, or a single top quark, $tH$. Events containing one or two electrons or muons are used for the measurement. In an extension of the Standard Model with a $CP$-odd admixture to the top-Higgs Yukawa coupling, the mixing angle between $CP$-even and $CP$-odd couplings is measured to be $\alpha=11\,^{\circ+52^{\circ}}_{ -73^{\circ}}$.

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ATLAS Collaboration. 2023-03-10. Probing the $CP$ nature of the top-Higgs Yukawa coupling in $t\bar{t}H$ and $tH$ events with $H \to b\bar{b}$ decays using the ATLAS detector at the LHC. https://doi.org/10.1016/j.physletb.2024.138469

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