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The gauging of the lepton flavour group is considered in the Standard Model context and in its extension with three right-handed neutrinos. The anomaly cancellation conditions lead to a Seesaw mechanism as underlying dynamics for all…

High Energy Physics - Phenomenology · Physics 2017-02-15 R. Alonso , E. Fernandez Martinez , M. B. Gavela , B. Grinstein , L. Merlo , P. Quilez

The present upper bound on $\kappa_e$, the ratio between the electron Yukawa coupling and its Standard Model value, is of ${\cal O}(600)$. We ask what would be the implications in case that $\kappa_e$ is close to this upper bound. The…

High Energy Physics - Phenomenology · Physics 2018-05-09 Avital Dery , Claudia Frugiuele , Yosef Nir

We study the constraints on $t\to u$ flavor changing neutral Higgs (FCNH) coupling, and how it may be explored further at the Large Hadron Collider (LHC). In the general two Higgs doublet model, such transitions can be induced by a nonzero…

High Energy Physics - Phenomenology · Physics 2020-09-16 Wei-Shu Hou , Ting-Hsiang Hsu , Tanmoy Modak

We discuss the possibility of interpreting the recent experimental hints, in favour of a 95 GeV resonance, with extensions of the Standard Model featuring an extra Higgs doublet and SM scalar (2HDM+s) or pseudoscalar singlet (2HDM+a). The…

High Energy Physics - Phenomenology · Physics 2025-01-15 Giorgio Arcadi , Giorgio Busoni , David Cabo-Almeida , Navneet Krishnan

Experimental study at LHC of the possible Higgs boson should soon provide accurate estimates of the Yukawa couplings $Y_{H\bar{f}f}$ for $f=t,b,\tau$. In the presence of a non-abelian discrete flavor symmetry $G_F$ (e.g. T') the usual…

High Energy Physics - Phenomenology · Physics 2013-01-04 Paul H. Frampton

Unitarity constraints for Yukawa couplings are considered in the Two Higgs Doublet Model type III, by using a general expansion in partial waves for fermionic scattering processes. Constraints over general Flavor Changing Neutral Currents…

High Energy Physics - Phenomenology · Physics 2014-08-07 Andres Castillo , Rodolfo A. Diaz , John Morales

The coupling of the Higgs boson to first and second generation fermions has yet to be measured experimentally. There still could be very large deviations in these couplings, as the origin of flavor is completely unknown. Nevertheless, if…

High Energy Physics - Phenomenology · Physics 2024-10-08 Artemis Sofia Giannakopoulou , Patrick Meade , Mauro Valli

The two-Higgs-doublet model provides a simple, yet interesting, generalization of the SM Higgs sector. We study the CP-conserving version of this model with general, flavor-diagonal, Yukawa couplings. Indirect constraints are obtained from…

High Energy Physics - Phenomenology · Physics 2015-05-14 Oscar Stål

The suppression of flavor and CP violation in supersymmetric theories may be due to the mechanism responsible for the structure of the Yukawa couplings. We study model independently the compatibility between low energy flavor and CP…

High Energy Physics - Phenomenology · Physics 2009-02-23 Yasunori Nomura , Daniel Stolarski

In the simplest examples of models with a discrete quark-lepton symmetry, an electroweak symmetry breaking sector with more than one Higgs doublet is necessary to obtain the correct mass relations between quarks and leptons. A two Higgs…

High Energy Physics - Phenomenology · Physics 2009-10-28 C. C. Lassig , R. R. Volkas

In these proceedings we review the flavour phenomenology of 2HDMs with generic Yukawa structures. We first consider the quark sector and find that despite the stringent constraints from FCNC processes large effects in tauonic B decays are…

High Energy Physics - Phenomenology · Physics 2022-08-09 Andreas Crivellin , Christoph Greub , Ahmet Kokulu

We start by presenting the current status of a complex flavour conserving two-Higgs doublet model. We will focus on some very interesting scenarios where unexpectedly the light Higgs couplings to leptons and to b-quarks can have a large…

High Energy Physics - Phenomenology · Physics 2015-03-06 Duarte Fontes , Jorge C. Romão , Rui Santos , João P. Silva

In most versions of beyond the standard model (BSM) physics, the Yukawa couplings of the quarks and charged leptons are not all to the same complex scalar doublet but to different ones. Comparison to the standard model (SM) with only one…

High Energy Physics - Phenomenology · Physics 2015-08-14 Paul H. Frampton , Thomas W. Kephart

We examine the decays $t\rightarrow c\gamma$ and $c Z^0$ in the Standard Model with an extra scalar doublet and no discrete symmetry preventing tree-level flavour changing neutral currents. The Yukawa couplings of the new scalars are…

High Energy Physics - Phenomenology · Physics 2009-10-22 Michael Luke , Martin J. Savage

We ask what new states may lie at or below the TeV scale, with sizable flavour-dependent couplings to light quarks, putting them within reach of hadron colliders via resonant production, or in association with Standard Model states. In…

High Energy Physics - Phenomenology · Physics 2011-09-07 Gian Francesco Giudice , Ben Gripaios , Raman Sundrum

We update phenomenological constraints on a Two Higgs Doublet Model with lepton flavour non-conserving Yukawa couplings. We review that $\tan \beta$ is ambiguous in such "Type III" models, and define it from the $\tau$ Yukawa coupling. The…

High Energy Physics - Phenomenology · Physics 2010-06-15 Sacha Davidson , Gerald Grenier

We perform an extensive study of flavor observables in a 2HDM with generic Yukawa structure (the decoupling limit of the MSSM). We examine the effects in flavor physics and constrain the model both from tree-level processes and…

High Energy Physics - Phenomenology · Physics 2013-08-19 Andreas Crivellin , Ahmet Kokulu , Christoph Greub

We discuss theoretical and phenomenological aspects of two-Higgs-doublet extensions of the Standard Model. In general, these extensions have scalar mediated flavour changing neutral currents which are strongly constrained by experiment.…

High Energy Physics - Phenomenology · Physics 2015-05-28 G. C. Branco , P. M. Ferreira , L. Lavoura , M. N. Rebelo , Marc Sher , Joao P. Silva

We consider constraints from flavor physics on two-Higgs-doublet models (2HDM) with general, flavor-diagonal, Yukawa couplings. Analyzing the charged Higgs contribution to different observables, we find that $b\to s\gamma$ transitions and…

High Energy Physics - Phenomenology · Physics 2010-02-19 Farvah Mahmoudi , Oscar Stål

We study Two-Higgs-Doublet Models (2HDM) where Abelian symmetries have been introduced, leading to a drastic reduction in the number of free parameters in the 2HDM. Our analysis is inspired in BGL models, where, as the result of a symmetry…

High Energy Physics - Phenomenology · Physics 2018-09-12 Joao M. Alves , Francisco J. Botella , Gustavo C. Branco , Fernando Cornet-Gomez , Miguel Nebot , Joao P. Silva