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Probing top-quark couplings indirectly at Higgs factories

We perform a global effective-field-theory analysis to assess the combined precision of Higgs couplings, triple gauge-boson couplings, and top-quark couplings, at future circular e + e − colliders, with a focus on runs below the production threshold. Deviations in the top-quark sector entering as on...

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Autores principales: Durieux, Gauthier, Gu, Jiayin, Vryonidou, Eleni, Zhang, Cen
Lenguaje:eng
Publicado: 2018
Materias:
Acceso en línea:https://dx.doi.org/10.1088/1674-1137/42/12/123107
http://cds.cern.ch/record/2638204
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author Durieux, Gauthier
Gu, Jiayin
Vryonidou, Eleni
Zhang, Cen
author_facet Durieux, Gauthier
Gu, Jiayin
Vryonidou, Eleni
Zhang, Cen
author_sort Durieux, Gauthier
collection CERN
description We perform a global effective-field-theory analysis to assess the combined precision of Higgs couplings, triple gauge-boson couplings, and top-quark couplings, at future circular e + e − colliders, with a focus on runs below the production threshold. Deviations in the top-quark sector entering as one-loop corrections are consistently taken into account in the Higgs and diboson processes. We find that future lepton colliders running at center-of-mass energies below the production threshold can still provide useful information on top-quark couplings, by measuring virtual top-quark effects. With rate and differential measurements, the indirect individual sensitivity achievable is better than at the high-luminosity LHC. However, strong correlations between the extracted top-quark and Higgs couplings are also present and lead to much weaker global constraints on top-quark couplings. This implies that a direct probe of top-quark couplings above the production threshold is also helpful for the determination of Higgs and triple-gauge-boson couplings. In addition, we find that below the production threshold, the top-quark Yukawa coupling can be determined by its loop corrections to all Higgs production and decay channels. Degeneracy with the ggh coupling can be resolved, and even a global limit is competitive with the prospects of a linear collider above the threshold. This provides an additional means of determining the top-quark Yukawa coupling indirectly at lepton colliders.
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institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2018
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spelling cern-26382042021-07-15T22:59:11Zdoi:10.1088/1674-1137/42/12/123107http://cds.cern.ch/record/2638204engDurieux, GauthierGu, JiayinVryonidou, EleniZhang, CenProbing top-quark couplings indirectly at Higgs factorieshep-exParticle Physics - Experimenthep-phParticle Physics - PhenomenologyWe perform a global effective-field-theory analysis to assess the combined precision of Higgs couplings, triple gauge-boson couplings, and top-quark couplings, at future circular e + e − colliders, with a focus on runs below the production threshold. Deviations in the top-quark sector entering as one-loop corrections are consistently taken into account in the Higgs and diboson processes. We find that future lepton colliders running at center-of-mass energies below the production threshold can still provide useful information on top-quark couplings, by measuring virtual top-quark effects. With rate and differential measurements, the indirect individual sensitivity achievable is better than at the high-luminosity LHC. However, strong correlations between the extracted top-quark and Higgs couplings are also present and lead to much weaker global constraints on top-quark couplings. This implies that a direct probe of top-quark couplings above the production threshold is also helpful for the determination of Higgs and triple-gauge-boson couplings. In addition, we find that below the production threshold, the top-quark Yukawa coupling can be determined by its loop corrections to all Higgs production and decay channels. Degeneracy with the ggh coupling can be resolved, and even a global limit is competitive with the prospects of a linear collider above the threshold. This provides an additional means of determining the top-quark Yukawa coupling indirectly at lepton colliders.We perform a global effective-field-theory analysis to assess the combined precision on Higgs couplings, triple gauge-boson couplings, and top-quark couplings, at future circular $e^+e^-$ colliders, with a focus on runs below the $t\bar t$ production threshold. Deviations in the top-quark sector entering as one-loop corrections are consistently taken into account in Higgs and diboson processes. We find that future lepton colliders running at center-of-mass energies below the $t\bar t$ production threshold can still provide useful information on top-quark couplings, by measuring virtual top-quark effects. With rate and differential measurements, the indirect individual sensitivity achievable is better than at the high-luminosity LHC. However, strong correlations between the extracted top-quark and Higgs couplings are also present and lead to much weaker global constraints on top-quark couplings. This implies that a direct probe of top-quark couplings above the $t\bar t$ production threshold is helpful also for the determination of Higgs and triple-gauge-boson couplings. In addition, we find that below the $e^+e^-\to t\bar th$ production threshold, the top-quark Yukawa coupling can be determined by its loop corrections to all Higgs production and decay channels. Degeneracy with the $ggh$ coupling can be resolved, and even a global limit is competitive with the prospects of a linear collider above the threshold. This provides an additional means of determining the top-quark Yukawa coupling indirectly at lepton colliders.arXiv:1809.03520DESY-18-142DESY 18-142CERN-TH-2018-193MITP/18-081oai:cds.cern.ch:26382042018-09-10
spellingShingle hep-ex
Particle Physics - Experiment
hep-ph
Particle Physics - Phenomenology
Durieux, Gauthier
Gu, Jiayin
Vryonidou, Eleni
Zhang, Cen
Probing top-quark couplings indirectly at Higgs factories
title Probing top-quark couplings indirectly at Higgs factories
title_full Probing top-quark couplings indirectly at Higgs factories
title_fullStr Probing top-quark couplings indirectly at Higgs factories
title_full_unstemmed Probing top-quark couplings indirectly at Higgs factories
title_short Probing top-quark couplings indirectly at Higgs factories
title_sort probing top-quark couplings indirectly at higgs factories
topic hep-ex
Particle Physics - Experiment
hep-ph
Particle Physics - Phenomenology
url https://dx.doi.org/10.1088/1674-1137/42/12/123107
http://cds.cern.ch/record/2638204
work_keys_str_mv AT durieuxgauthier probingtopquarkcouplingsindirectlyathiggsfactories
AT gujiayin probingtopquarkcouplingsindirectlyathiggsfactories
AT vryonidoueleni probingtopquarkcouplingsindirectlyathiggsfactories
AT zhangcen probingtopquarkcouplingsindirectlyathiggsfactories