Search for flavour-changing neutral tqH interactions with H → γγ in pp collisions at $$ \sqrt{s} $$ = 13 TeV using the ATLAS detector



Aad, G, Abbott, B, Abeling, K, Abicht, NJ, Abidi, SH, Aboulhorma, A, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS
et al (show 2938 more authors) (2023) Search for flavour-changing neutral tqH interactions with H → γγ in pp collisions at $$ \sqrt{s} $$ = 13 TeV using the ATLAS detector. Journal of High Energy Physics, 2023 (12). 195-.

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Abstract

<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>A search for flavour-changing neutral interactions involving the top quark, the Higgs boson and an up-type quark <jats:italic>q</jats:italic> (<jats:italic>q</jats:italic> = <jats:italic>c, u</jats:italic>) is presented. The proton-proton collision data set used, with an integrated luminosity of 139 fb<jats:sup><jats:italic>−</jats:italic>1</jats:sup>, was collected at <jats:inline-formula><jats:alternatives><jats:tex-math>$$ \sqrt{s} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math></jats:alternatives></jats:inline-formula> = 13 TeV by the ATLAS experiment at the Large Hadron Collider. Both the decay process <jats:italic>t</jats:italic> → <jats:italic>qH</jats:italic> in <jats:inline-formula><jats:alternatives><jats:tex-math>$$ t\overline{t} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math></jats:alternatives></jats:inline-formula> production and the production process <jats:italic>pp</jats:italic> → <jats:italic>tH</jats:italic>, with the Higgs boson decaying into two photons, are investigated. No significant excess is observed and upper limits are set on the <jats:italic>t</jats:italic> → <jats:italic>cH</jats:italic> and the <jats:italic>t</jats:italic> → <jats:italic>uH</jats:italic> branching ratios of 4<jats:italic>.</jats:italic>3 × 10<jats:sup><jats:italic>−</jats:italic>4</jats:sup> and 3<jats:italic>.</jats:italic>8 × 10<jats:sup><jats:italic>−</jats:italic>4</jats:sup>, respectively, at the 95% confidence level, while the expected limits in the absence of signal are 4<jats:italic>.</jats:italic>7 × 10<jats:sup><jats:italic>−</jats:italic>4</jats:sup> and 3<jats:italic>.</jats:italic>9 × 10<jats:sup><jats:italic>−</jats:italic>4</jats:sup>. Combining this search with ATLAS searches in the <jats:italic>H</jats:italic> → <jats:italic>τ</jats:italic><jats:sup>+</jats:sup><jats:italic>τ</jats:italic><jats:sup><jats:italic>−</jats:italic></jats:sup> and <jats:italic>H</jats:italic> → <jats:inline-formula><jats:alternatives><jats:tex-math>$$ b\overline{b} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>b</mml:mi> <mml:mover> <mml:mi>b</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math></jats:alternatives></jats:inline-formula> final states yields observed (expected) upper limits on the <jats:italic>t</jats:italic> → <jats:italic>cH</jats:italic> branching ratio of 5<jats:italic>.</jats:italic>8 × 10<jats:sup><jats:italic>−</jats:italic>4</jats:sup> (3<jats:italic>.</jats:italic>0 × 10<jats:sup><jats:italic>−</jats:italic>4</jats:sup>) at the 95% confidence level. The corresponding observed (expected) upper limit on the <jats:italic>t → uH</jats:italic> branching ratio is 4<jats:italic>.</jats:italic>0 <jats:italic>×</jats:italic> 10<jats:sup><jats:italic>−</jats:italic>4</jats:sup> (2<jats:italic>.</jats:italic>4 <jats:italic>×</jats:italic> 10<jats:sup><jats:italic>−</jats:italic>4</jats:sup>).</jats:p>

Item Type: Article
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 16 Feb 2024 09:50
Last Modified: 17 Mar 2024 19:17
DOI: 10.1007/jhep12(2023)195
Open Access URL: https://link.springer.com/article/10.1007/JHEP12(2...
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3178688