The charge-parity (CP) structure of the Yukawa interaction between the Higgs (H) boson and the top quark is measured in a data sample enriched in the t t ¯ H and tH associated production, using 138 fb−1 of data collected in proton-proton collisions at s = 13 TeV by the CMS experiment at the CERN LHC. The study targets events where the H boson decays via H → WW or H → ττ and the top quarks decay via t → Wb: the W bosons decay either leptonically or hadronically, and final states characterized by the presence of at least two leptons are studied. Machine learning techniques are applied to these final states to enhance the separation of CP -even from CP -odd scenarios. Two-dimensional confidence regions are set on κ t and κ~ t, which are respectively defined as the CP -even and CP -odd top-Higgs Yukawa coupling modifiers. No significant fractional CP -odd contributions, parameterized by the quantity | fCPHtt | are observed; the parameter is determined to be | fCPHtt | = 0.59 with an interval of (0.24, 0.81) at 68% confidence level. The results are combined with previous results covering the H → ZZ and H → γγ decay modes, yielding two- and one-dimensional confidence regions on κ t and κ~ t, while | fCPHtt | is determined to be | fCPHtt | = 0.28 with an interval of | fCPHtt | < 0.55 at 68% confidence level, in agreement with the standard model CP -even prediction of | fCPHtt | = 0. [Figure not available: see fulltext.]. © 2023, The Author(s).

Search for CP violation in t t ¯ H and tH production in multilepton channels in proton-proton collisions at √s = 13 TeV

Ligabue, F.
Membro del Collaboration Group
;
2023

Abstract

The charge-parity (CP) structure of the Yukawa interaction between the Higgs (H) boson and the top quark is measured in a data sample enriched in the t t ¯ H and tH associated production, using 138 fb−1 of data collected in proton-proton collisions at s = 13 TeV by the CMS experiment at the CERN LHC. The study targets events where the H boson decays via H → WW or H → ττ and the top quarks decay via t → Wb: the W bosons decay either leptonically or hadronically, and final states characterized by the presence of at least two leptons are studied. Machine learning techniques are applied to these final states to enhance the separation of CP -even from CP -odd scenarios. Two-dimensional confidence regions are set on κ t and κ~ t, which are respectively defined as the CP -even and CP -odd top-Higgs Yukawa coupling modifiers. No significant fractional CP -odd contributions, parameterized by the quantity | fCPHtt | are observed; the parameter is determined to be | fCPHtt | = 0.59 with an interval of (0.24, 0.81) at 68% confidence level. The results are combined with previous results covering the H → ZZ and H → γγ decay modes, yielding two- and one-dimensional confidence regions on κ t and κ~ t, while | fCPHtt | is determined to be | fCPHtt | = 0.28 with an interval of | fCPHtt | < 0.55 at 68% confidence level, in agreement with the standard model CP -even prediction of | fCPHtt | = 0. [Figure not available: see fulltext.]. © 2023, The Author(s).
2023
Settore FIS/01 - Fisica Sperimentale
CP Violation; Hadron-Hadron Scattering; Higgs Physics
   Advanced Multi-Variate Analysis for New Physics Searches at the LHC
   AMVA4NewPhysics
   European Commission
   Horizon 2020 Framework Programme
   675440

   Search for Higgs bosons decaying to charm quarks
   HIGCC
   European Commission
   Horizon 2020 Framework Programme
   724704

   Direct and indirect searches for new physics in events with top quarks using LHC proton-proton collisions at the CMS detector
   LHCTOPVLQ
   European Commission
   Horizon 2020 Framework Programme
   752730

   Majorana neutrino discovery strategy with CMS
   MajorNet
   European Commission
   Horizon 2020 Framework Programme
   758316

   International Training Network for Statistics in High Energy Physics and Society
   INSIGHTS
   European Commission
   Horizon 2020 Framework Programme
   765710

   The strong interaction at the frontier of knowledge: fundamental research and applications
   STRONG-2020
   European Commission
   Horizon 2020 Framework Programme
   824093

   International, Interdisciplinary & Intersectoral Postdoctoral Fellowships at the Paul Scherrer Institut
   PSI-FELLOW-III-3i
   European Commission
   Horizon 2020 Framework Programme
   884104
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/139582
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