There is no guarantee that the violation of lepton number, assuming it exists, will primarily manifest itself in neutrinoless double beta decay. Lepton-number violation and lepton-flavor violation may be related, and one complementary observable to double beta decay is muon-to-positron conversion. In this talk, I will discuss an effective field theory approach to estimating muon-to-positron...

A plethora of ultraviolet completions of the Standard Model have extra U(1) gauge symmetries. In general, the associated massive $Z^\prime$ gauge boson can mediate flavor-changing neutral current processes at tree level. We consider a situation where the $Z^\prime$ boson couples solely via flavor-changing interactions to quarks and leptons. In this scenario the model parameter space is, in...

We argue that lepton flavor violating (LFV) decays $M \to \ell_1 \overline \ell_2$ of quarkonium and heavy quark meson states $M$ with different quantum numbers could be used to put constraints on the Wilson coefficients of effective operators describing LFV interactions at low energy scales. We note that the restricted kinematics of the two-body decay of quarkonium or a heavy quark meson...

An alternative left-right model of quarks and leptons, where the SU(2)$_R$ lepton doublet $(\nu, l)_R$ is replaced with (n, l)$_R$ so that n$_R$ is not the Dirac mass partner of $\nu_L$,has been known since 1987. Previous versions assumed a global U(1)$_S$ symmetry to allow n to be identified as a dark-matter fermion (scotino). We propose here a gauge extension by the addition of extra...

Grand Unified Theories (GUTs) are well-motivated extensions of the Standard Model. They represent a theoretically sound approach to explore physics at very high scales given the lack of firm signs of new physics near the electroweak scale. This talk will focus on SO(10)-symmetric models with a two-step symmetry breaking chain, where the only intermediate scale respects the left-right symmetric...

We propose a simple left-right symmetric model which generates radiative majorana neutrino masses through the Zee mechanism. Its scalar content is composed of the minimal degrees of freedom required for symmetry breaking and mass generation plus a singlet charged higgs which, along with the softly broken left-right symmetry in the yukawa sector, is responsible of the radiative neutrino masses...

In this talk we discuss the sensitivity of probing light scalars in the Borexino detector, and the possibility of detecting heavy leptons in the SHiP and DUNE experiments.

First we address in detail the sensitivity of the Borexino-SOX conﬁguration in detecting light scalar particles coupled to the SM fermions. Within one year of operations one can achieve an unprecedented sensitivity to the...

We point out that in generic TeV scale seesaw models for neutrino masses with

local B −L symmetry breaking, the Higgs field breaking the B −L symmetry can leave a physical real scalar field with mass around GeV scale. In the specific case when the B − L symmetry is embedded into the left-right symmetry, low energy flavor constraints necessarily require the light scalar to be long lived, with...