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Recent results from the intensity frontier indicate the tantalizing possibility of violation in lepton flavour universality. In light of this we revisit the minimal phenomenological $Z'$ model taking in account both vectorial and…

High Energy Physics - Phenomenology · Physics 2023-01-03 Tirtha Sankar Ray , Avirup Shaw

We demonstrate that flavour-changing neutral currents in the top sector, mediated by leptophilic scalars at the electroweak scale, can easily arise in scenarios of new physics, and in particular in composite Higgs models. We moreover show…

High Energy Physics - Phenomenology · Physics 2020-10-14 Nuno Castro , Mikael Chala , Ana Peixoto , Maria Ramos

We introduce the idea of flavour transfer from a non-abelian horizontal $SU(2)_f$ flavour gauge group embedded in the Standard Model flavour structure. The new flavour vector bosons, in the mass range from the tens of GeV to multi-TeV do…

High Energy Physics - Phenomenology · Physics 2024-06-21 Luc Darmé , Aldo Deandrea , Farvah Mahmoudi

Leptoquarks (LQs) have been extensively studied in the context of $B$ anomalies. When $U(1)_{L_\mu-L_\tau}$ is introduced to a scalar LQ model with the LQ $S_1$ charged under the new symmetry, $S_1$ primarily couples to the third-generation…

High Energy Physics - Phenomenology · Physics 2023-10-05 Chuan-Hung Chen , Cheng-Wei Chiang

We present a particular warped extra dimensional model, where the flavour diagonal and flavour non-diagonal Z boson couplings to left-handed down quarks are protected by the custodial symmetry P_LR. After a brief introduction of the model…

High Energy Physics - Phenomenology · Physics 2009-07-22 Stefania Gori

We propose a mass matrix model that gives a unified description of quark and lepton with the same texture form based on a flavor 2 <-> 3 symmetry. The model is in contrast with the conventional picture that the mass matrix forms in the…

High Energy Physics - Phenomenology · Physics 2009-11-11 Koichi Matsuda , Hiroyuki Nishiura

The LHC is a top quark factory and provides a unique opportunity to look for flavour changing neutral current or charged-lepton flavour violating interactions of the top quark. These processes are highly suppressed in the Standard Model and…

High Energy Physics - Experiment · Physics 2024-01-17 Pavol Bartos

A complete study on the fermion masses and flavor mixing is presented in a non-minimal left-right symmetric model (NMLRMS) where the ${\bf S}_{3}\otimes {\bf Z}_{2}\otimes {\bf Z}^{e}_{2}$ flavor symmetry drives the Yukawa couplings. In the…

High Energy Physics - Phenomenology · Physics 2018-10-30 E. A. Garcés , Juan Carlos Gómez-Izquierdo , F. Gonzalez-Canales

In multi-Higgs-doublet models, the alignment in flavour space of all Yukawa matrices coupling to a given right-handed fermion guarantees the absence of tree-level flavour-changing neutral couplings, while introducing new sources of CP…

High Energy Physics - Phenomenology · Physics 2011-04-05 Antonio Pich

We probe the unification of down quarks and leptons in a supersymmetric SO(10) GUT. The large atmospheric neutrino mixing angle induces bR-sR transitions, which can account for the sizeable CP phase measured in Bs-Bsbar mixing. Corrections…

High Energy Physics - Phenomenology · Physics 2015-05-14 Susanne Westhoff

LHCb has reported deviations from the Standard Model in $b\to s\mu^+\mu^-$ transitions for which a new neutral gauge boson is a prime candidate for an explanation. As this gauge boson has to couple in a flavour non-universal way to muons…

High Energy Physics - Phenomenology · Physics 2015-09-25 Andreas Crivellin , Lars Hofer , Joaquim Matias , Ulrich Nierste , Stefan Pokorski , Janusz Rosiek

We use a $U(2)\times U(1)$ horizontal symmetry in order to construct supersymmetric models where the flavor structure of both quarks and leptons is induced naturally. The supersymmetric flavor changing neutral currents problem is solved by…

High Energy Physics - Phenomenology · Physics 2009-10-31 Galit Eyal

Based on a new approach to quark and lepton masses, where the mass spectra originate in vacuum expectation values of O(3)-flavor 1+5 (gauge singlet) scalars, a neutrino mass matrix of a new type is speculated. The mass matrix is described…

High Energy Physics - Phenomenology · Physics 2009-11-13 Yoshio Koide

We propose a flavour structure for the leptonic sector of the Standard Model, based on the idea of universality of Yukawa couplings, which accommodates all the experimental data on neutrino masses and mixing, at the same time predicting…

High Energy Physics - Phenomenology · Physics 2010-04-05 G. C. Branco , M. N. Rebelo , J. I. Silva-Marcos

We propose a E_6 inspired supersymmetric model with a non-Abelian discrete flavor symmetry (S_4 group); that is, SU(3)_c x SU(2)_W x U(1)_Y x U(1)_X x S_4 x Z_2. In our scenario, the additional abelian gauge symmetry; U(1)_X, not only…

High Energy Physics - Phenomenology · Physics 2014-11-20 Y. Daikoku , H. Okada

Over the last ten years tri-bimaximal mixing has played an important role in modeling the flavour problem. We give a short review of the status of flavour symmetry models of neutrino mixing. We concentrate on non-Abelian discrete…

High Energy Physics - Phenomenology · Physics 2015-06-05 S. Morisi , J. W. F. Valle

We derive constraints on the mixing of heavy right-handed neutrinos with the SM fields in the most general Seesaw scenario where the heavy neutrinos are integrated out. Among the electroweak and flavour observables included in the global…

High Energy Physics - Phenomenology · Physics 2016-11-24 Josu Hernandez-Garcia

The measurements of the ratios $R_{K^{(*)}}$ along with $R_{D^{(*)}}$ hint towards lepton flavor non universality which is in disagreement with the standard model. In this work, we reanalyze the four new physics models, which are widely…

High Energy Physics - Phenomenology · Physics 2019-08-27 Ashutosh Kumar Alok , Jacky Kumar , Dinesh Kumar , Ruchi Sharma

In the simplest (non-quiver) unified theories, fermion families are often treated sequentially and a flavor symmetry may act similarly. As an alternative with non-sequential flavor symmetry, we consider a model based on the group…

High Energy Physics - Phenomenology · Physics 2011-08-12 David A. Eby , Paul H. Frampton , Xiao-Gang He , Thomas W. Kephart

A variety of lepton flavour violating effects related to the recent discovery of neutrino oscillations and mixings is here systematically discussed in terms of an S_3-flavour permutational symmetry. After a brief review of some relevant…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Mondragón , M. Mondragón , E. Peinado