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Composite Higgs-mediated flavor-changing neutral current

We discuss how, in the presence of higher-dimensional operators, the Standard Model (SM) fermion masses can be misaligned in flavor space with the Yukawa couplings to the Higgs boson, even with only one Higgs doublet. Such misalignment results in flavor-violating couplings to the Higgs and hence fla...

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Detalles Bibliográficos
Autores principales: Agashe, Kaustubh, Contino, Roberto
Lenguaje:eng
Publicado: 2009
Materias:
Acceso en línea:https://dx.doi.org/10.1103/PhysRevD.80.075016
http://cds.cern.ch/record/1233196
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author Agashe, Kaustubh
Contino, Roberto
author_facet Agashe, Kaustubh
Contino, Roberto
author_sort Agashe, Kaustubh
collection CERN
description We discuss how, in the presence of higher-dimensional operators, the Standard Model (SM) fermion masses can be misaligned in flavor space with the Yukawa couplings to the Higgs boson, even with only one Higgs doublet. Such misalignment results in flavor-violating couplings to the Higgs and hence flavor-changing neutral current processes from tree-level Higgs exchange. We perform a model-independent analysis of such an effect. Specializing to the framework of a composite Higgs with partially composite SM gauge and fermion fields, we show that the constraints on the compositeness scale implied by epsilon_K can be generically as strong as those from the exchange of heavy spin-1 resonances if the Higgs is light and strongly coupled to the new states. In the special and well motivated case of a composite pseudo-Goldstone Higgs, we find that the shift symmetry acting on the Higgs forces an alignment of the fermion mass terms with their Yukawa couplings at leading order in the fermions' degree of compositeness, thus implying much milder bounds. As a consequence of the flavor-violating Higgs couplings, we estimate BR(t -> c h)~ 10^{-4} and BR(h -> tc)~ 5 x 10^{-3} both for a pseudo-Goldstone (if t_R is fully composite) and for a generic composite Higgs. By virtue of the AdS/CFT correspondence, our results directly apply to 5-dimensional Randall-Sundrum compactifications.
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spelling cern-12331962019-09-30T06:29:59Zdoi:10.1103/PhysRevD.80.075016http://cds.cern.ch/record/1233196engAgashe, KaustubhContino, RobertoComposite Higgs-mediated flavor-changing neutral currentParticle Physics - PhenomenologyWe discuss how, in the presence of higher-dimensional operators, the Standard Model (SM) fermion masses can be misaligned in flavor space with the Yukawa couplings to the Higgs boson, even with only one Higgs doublet. Such misalignment results in flavor-violating couplings to the Higgs and hence flavor-changing neutral current processes from tree-level Higgs exchange. We perform a model-independent analysis of such an effect. Specializing to the framework of a composite Higgs with partially composite SM gauge and fermion fields, we show that the constraints on the compositeness scale implied by epsilon_K can be generically as strong as those from the exchange of heavy spin-1 resonances if the Higgs is light and strongly coupled to the new states. In the special and well motivated case of a composite pseudo-Goldstone Higgs, we find that the shift symmetry acting on the Higgs forces an alignment of the fermion mass terms with their Yukawa couplings at leading order in the fermions' degree of compositeness, thus implying much milder bounds. As a consequence of the flavor-violating Higgs couplings, we estimate BR(t -> c h)~ 10^{-4} and BR(h -> tc)~ 5 x 10^{-3} both for a pseudo-Goldstone (if t_R is fully composite) and for a generic composite Higgs. By virtue of the AdS/CFT correspondence, our results directly apply to 5-dimensional Randall-Sundrum compactifications.arXiv:0906.1542CERN-PH-TH-2009-085oai:cds.cern.ch:12331962009-06-09
spellingShingle Particle Physics - Phenomenology
Agashe, Kaustubh
Contino, Roberto
Composite Higgs-mediated flavor-changing neutral current
title Composite Higgs-mediated flavor-changing neutral current
title_full Composite Higgs-mediated flavor-changing neutral current
title_fullStr Composite Higgs-mediated flavor-changing neutral current
title_full_unstemmed Composite Higgs-mediated flavor-changing neutral current
title_short Composite Higgs-mediated flavor-changing neutral current
title_sort composite higgs-mediated flavor-changing neutral current
topic Particle Physics - Phenomenology
url https://dx.doi.org/10.1103/PhysRevD.80.075016
http://cds.cern.ch/record/1233196
work_keys_str_mv AT agashekaustubh compositehiggsmediatedflavorchangingneutralcurrent
AT continoroberto compositehiggsmediatedflavorchangingneutralcurrent