Related papers: Non-universal Z' models with protected flavour-cha…
We investigate a gauge extension of the Standard Model in light of the observed hints of lepton universality violation in $b \to c \ell \nu$ and $b \to s \ell^+ \ell^-$ decays at BaBar, Belle and LHCb. The model consists of an extended…
A minimal extension of the Standard Model (SM) featuring two scalar leptoquarks, an SU(2) doublet with hypercharge 1/6 and a singlet with hypercharge 1/3, is proposed as an economical benchmark model for studies of an interplay between…
Since the discovery of neutrino oscillations many ideas have been put forward to explain the special features of the leptonic mixing and the differences with respect to the quark sector. In this talk I review some of these proposals,…
Naturally small neutrino masses can arise in some grand unified models. The mechanism of neutrino mass generation in these models typically requires the existence of neutral heavy leptons. We study the low-energy phenomenology of these new…
We consider an abelian extension of the Standard Model (SM) comprising a new gauge group $U(1)^\prime$, with the neutral gauge boson $Z^\prime$ having flavour violating couplings to quarks and leptons. The fermion content is the same as in…
We study the phenomenology of simplified $Z^\prime$ models with a global $U(2)^3$ flavour symmetry in the quark sector, broken solely by the Standard Model Yukawa couplings. This flavour symmetry, known as less-minimal flavour violation,…
Flavor symmetries that explain masses and mixings of the standard model fermions dictate flavor patterns for the couplings of scalar and vector leptoquarks to the standard model fermions. A generic feature is that couplings to…
An interesting mass relation between down type quarks and charged leptons has been recently predicted within a supersymmetric SU(3)_c \times SU(2)_L \times U(1)_Y model based on the A4 flavor symmetry. Here we propose a simple extension…
We build a class of two-Higgs-doublet models in which the flavour-changing couplings of the neutral scalars are related in an exact way to elements of the quark mixing matrix. In this framework, we explore the different possibilities for CP…
Experimental hints for lepton-flavor universality violation in the muon's magnetic moment as well as neutral- and charged-current $B$-meson decays require Standard-Model extensions by particles such as leptoquarks that generically lead to…
The smallness of fermion masses and mixing angles has recently been been attributed to approximate global $U(1)$ symmetries, one for each fermion type. The parameters associated with these symmetry breakings are estimated here directly from…
We study flavor violating processes in the production or decay of a neutral pseudoscalar meson $P^0$ in the framework of a general two Higgs Doublet Model type III (2HDM-III). We use a version of the model where Yukawa interactions of…
We present a new class of models of lepton flavor in the composite Higgs framework. Following the concept of minimality, they lead to a rich phenomenology in good agreement with the current experimental picture. Because of a unification of…
We propose a hidden gauged $U(1)_H$ $Z'$ model to explain deviations from the Standard Model (SM) values in lepton flavor universality known as $R_K$ and $R_D$ anomalies. The $Z'$ only interacts with the SM fermions via their mixing with…
The coming flavour precision era will allow to uncover various patterns of flavour violation in different New Physics scenarios. We discuss different classes of them. A simple extension of the Standard Model that generally introduces new…
Lepton-flavour symmetry in the Standard Model is broken by small masses for charged leptons and neutrinos. Introducing neutrino masses via dimension-5 operators associated to lepton-number violation at a very high scale, the corresponding…
We show that one can describe the quark and lepton masses with a single anomaly-free U(1) flavor symmetry provided a single order one parameter is enhanced by roughly 4-5. The flavor symmetry can be seen to arise from inside the $E_6$…
We present a general phenomenological analysis of a class of Two Higgs Doublet Models with Flavor Changing Neutral Currents arising at the tree level. The existing constraints mainly affect the couplings of the first two generations of…
We produce five flavour models for the lepton sector. All five models fit perfectly well---at the one-sigma level---the existing data on the neutrino mass-squared differences and on the lepton mixing angles. The models are based on the…
In extended Higgs models, a discrete symmetry is needed in the quark sector to avoid tree-level flavor-changing neutral currents. However, this is not necessary the case in the lepton sector. We consider a model in which one Higgs couples…