In this talk we discuss various Theories of Flavour from the Planck scale to the Electroweak Scale, ranging from SUSY GUTs with Flavour Symmetry (with or without extra dimensions) to Flavourful Z' Models at the Electroweak scale capable of accounting for R_K(*).

I will discuss an extension of the Standard Model (SM) by a full new generation of quarks and leptons which are vector-like (VL) under the SM gauge group but chiral with respect to a new flavor dependent U(1) gauge symmetry. The model can simultaneously explain the deviations of the muon g-2 and lepton flavor universality in B-meson decays without conflicting with the data on Higgs decays,...

We will consider solving the neutral current B anomalies called the R_K and R_K^* puzzles with light mediators. We will lay out the conditions required to solve the anomalies and be consistent will all constraints. We will then consider a scenario where the required interaction can arise and consider the implications in other sectors like coherent neutrino scattering.

We present the study of processes in current experiments to search for heavy sterile neutrinos, particles which appear as natural extensions of the Standard Model spectrum, whose presence will explain the tiny masses of the known neutrinos. While the simplest explanation of these tiny masses is by a seesaw mechanism where extra neutral leptons have masses way up to GUT scales, there are many...

Neutrinoless double beta (0vbb) decay is the most powerful tool to probe not only for Majorana neutrino masses but for lepton number violating physics in general. I will discuss the connections between lepton number violation, double beta decay and neutrino mass, highlighting recent experimental and theoretical efforts. Extending the standard picture of light neutrino exchange, I will review a...

The hope of relating fermion masses and mixing angles to

some fundamental underlying principle, has fostered an intense activity

aimed at identifying possible symmetry patterns in the data.

Neutrino masses and lepton mixing angles have played an important

role in such attempts. In this talk I will illustrate a new class of models where

the role of flavour symmetry is played by the modular...

In this talk, we fully discuss the old idea of parametrizing fermion mixing through the corresponding fermion masses. We begin by showing how 't Hooft's criteria for naturalness could be employed to build a new mixing parametrization with the right behaviour to allow the emergence of new symmetries, whenever considering either the first or the first two lightest families equal to zero....

It is well known that a mass relation for the charged leptons,

$(m_e +m_\mu + m_\tau)/(\sqrt{m_e} +\sqrt{m_\mu} +\sqrt{m_\tau})^2
=2/3$, is excellently satisfied by the observed masses (pole mass).

However, this excellent coincidence is just a big problem, because

``mass" in a field theoretical model means a running mass, not

pole mass. For this problem, Sumino has proposed a way out by...