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Search for flavour-changing neutral tqH interactions with H → γγ in pp collisions at (Formula presented.) TeV using the ATLAS detector

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Aad, G 
Abbott, B 
Abeling, K 
Abicht, NJ 
Abidi, SH 


jats:titleAjats:scbstract</jats:sc> </jats:title>jats:pA search for flavour-changing neutral interactions involving the top quark, the Higgs boson and an up-type quark jats:italicq</jats:italic> (jats:italicq</jats:italic> = jats:italicc, u</jats:italic>) is presented. The proton-proton collision data set used, with an integrated luminosity of 139 fbjats:supjats:italic−</jats:italic>1</jats:sup>, was collected at jats:inline-formulajats:alternativesjats:tex-math$$ \sqrt{s} $$</jats:tex-math><mml:math xmlns:mml=""> mml:msqrt mml:mis</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:italict</jats:italic> → jats:italicqH</jats:italic> in jats:inline-formulajats:alternativesjats:tex-math$$ t\overline{t} $$</jats:tex-math><mml:math xmlns:mml=""> mml:mit</mml:mi> mml:mover mml:mit</mml:mi> mml:mo¯</mml:mo> </mml:mover> </mml:math></jats:alternatives></jats:inline-formula> production and the production process jats:italicpp</jats:italic> → jats:italictH</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:italict</jats:italic> → jats:italiccH</jats:italic> and the jats:italict</jats:italic> → jats:italicuH</jats:italic> branching ratios of 4jats:italic.</jats:italic>3 × 10jats:supjats:italic−</jats:italic>4</jats:sup> and 3jats:italic.</jats:italic>8 × 10jats:supjats:italic−</jats:italic>4</jats:sup>, respectively, at the 95% confidence level, while the expected limits in the absence of signal are 4jats:italic.</jats:italic>7 × 10jats:supjats:italic−</jats:italic>4</jats:sup> and 3jats:italic.</jats:italic>9 × 10jats:supjats:italic−</jats:italic>4</jats:sup>. Combining this search with ATLAS searches in the jats:italicH</jats:italic> → jats:italicτ</jats:italic>jats:sup+</jats:sup>jats:italicτ</jats:italic>jats:supjats:italic−</jats:italic></jats:sup> and jats:italicH</jats:italic> → jats:inline-formulajats:alternativesjats:tex-math$$ b\overline{b} $$</jats:tex-math><mml:math xmlns:mml=""> mml:mib</mml:mi> mml:mover mml:mib</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:italict</jats:italic> → jats:italiccH</jats:italic> branching ratio of 5jats:italic.</jats:italic>8 × 10jats:supjats:italic−</jats:italic>4</jats:sup> (3jats:italic.</jats:italic>0 × 10jats:supjats:italic−</jats:italic>4</jats:sup>) at the 95% confidence level. The corresponding observed (expected) upper limit on the jats:italict → uH</jats:italic> branching ratio is 4jats:italic.</jats:italic>0 jats:italic×</jats:italic> 10jats:supjats:italic−</jats:italic>4</jats:sup> (2jats:italic.</jats:italic>4 jats:italic×</jats:italic> 10jats:supjats:italic−</jats:italic>4</jats:sup>).</jats:p>


Acknowledgements: We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently. We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; ANID, Chile; CAS, MOST and NSFC, China; Minciencias, Colombia; MEYS CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS and CEA-DRF/IRFU, France; SRNSFG, Georgia; BMBF, HGF and MPG, Germany; GSRI, Greece; RGC and Hong Kong SAR, China; ISF and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; NWO, Netherlands; RCN, Norway; MEiN, Poland; FCT, Portugal; MNE/IFA, Romania; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZŠ, Slovenia; DSI/NRF, South Africa; MICINN, Spain; SRC and Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Taiwan; TENMAK, Türkiye; STFC, United Kingdom; DOE and NSF, United States of America. In addition, individual groups and members have received support from BCKDF, CANARIE, Compute Canada and CRC, Canada; PRIMUS 21/SCI/017 and UNCE SCI/013, Czech Republic; COST, ERC, ERDF, Horizon 2020, ICSC-NextGenerationEU and Marie Skłodowska-Curie Actions, European Union; Investissements d’Avenir Labex, Investissements d’Avenir Idex and ANR, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF, Greece; BSF-NSF and MINERVA, Israel; Norwegian Financial Mechanism 2014-2021, Norway; NCN and NAWA, Poland; La Caixa Banking Foundation, CERCA Programme Generalitat de Catalunya and PROMETEO and GenT Programmes Generalitat Valenciana, Spain; Göran Gustafssons Stiftelse, Sweden; The Royal Society and Leverhulme Trust, United Kingdom. The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN, the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Germany), INFN-CNAF (Italy), NL-T1 (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (U.K.) and BNL (U.S.A.), the Tier-2 facilities worldwide and large non-WLCG resource providers. Major contributors of computing resources are listed in ref. [104].


5106 Nuclear and Plasma Physics, 5107 Particle and High Energy Physics, 51 Physical Sciences

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