Alessio Giarnetti

A bstract: The flavour composition of a future supernova neutrino signal is expected to carry measurable imprints of flavour conversion processes in the dense stellar medium. In this work, we analyse the sensitivity of the upcoming Deep Underground Neutrino Experiment (DUNE) to three phenomenologically distinct effects: slow energy-dependent collective oscillations, fast energy-independent collective oscillations, and standard MSW conversions. By integrating GLoBES and MultiNest and using benchmark neutrino fluxes at emission, we assess the potential of DUNE to extract the underlying flux parameters and discriminate among conversion scenarios.

A bstract: We build upon a simple U(2) _F model of flavor, in which all fermion masses and mixing hierarchies arise from powers of two small parameters controlling U(2) _F breaking. In the original formulation, an isomorphism to the discrete D ₆ × U(1) _F symmetry was invoked to generate a Majorana neutrino mass term. Here, we retain the successful features of that model for the charged leptons and quarks, while exploring alternative neutrino charge assignments within the U(2) _F framework. This approach allows us to generate Majorana neutrino masses via the see-saw mechanism without introducing any additional symmetries nor invoking any isomorphism. We further examine the implications of our models for Lepton Flavor Violating (LFV) decays, analyzing the processes μ → eγ , τ → μγ and τ → eγ and their connection with the leptonic anomalous magnetic moments. We show that within the Standard Model Effective Field Theory (SMEFT) approach the current limits on the branching ratios of μ → eγ LFV decays obtained in our U(2) _F models are not compatible with the central value of the recent measurement of the ( g − 2) _μ , thereby suggesting that either ( g − 2) _μ must be very close to the Standard Model predictions, as the latest experimental and theoretical results seem to suggest, or the invoked flavor symmetry is not appropriate to describe an anomalous muon magnetic moment.

This short review discusses recent applications of Reinforcement Learning (RL) techniques to the flavor problem in particle physics. Traditional approaches to fermion masses and mixing often rely on extensions of the Standard Model based on horizontal symmetries, but the vast landscape of possible models makes systematic exploration infeasible. Recent works have shown that RL can efficiently navigate this landscape by constructing models that reproduce observed quark and lepton observables. These approaches demonstrate that RL not only rediscovers models already proposed in the literature but also uncovers new, phenomenologically acceptable solutions.

A bstract: Neutrino oscillations constitute an excellent tool to probe physics beyond the Standard Model. In this paper, we investigate the potential of the ESSnuSB experiment to constrain the effects of flavour-dependent long-range forces (LRFs) in neutrino oscillations, which may arise due to the extension of the Standard Model gauge group by introducing new U(1) symmetries. Focusing on three specific U(1) symmetries — L _e − L _μ , L _e − L _τ , and L _μ − L _τ , we demonstrate that ESSnuSB offers a favourable environment to search for LRF effects. Our analyses reveal that ESSnuSB can set 90% confidence level bounds of V _eμ < 2.99 × 10 ^{− 14} eV, V _eτ < 2.05 × 10 ^{− 14} eV, and V _μτ < 1.81 × 10 ^{− 14} eV, which are competitive to the upcoming Deep Underground Neutrino Experiment (DUNE). It is also observed that reducing the systematic uncertainties from 5% to 2% improves the ESSnuSB limits on V _αβ . Interestingly, we find limited correlations between LRF parameters and the less constrained lepton mixing parameters θ ₂₃ and δ _CP , preserving the robustness of ESSnuSB’s sensitivity to CP violation. Even under extreme LRF potentials ( V _αβ ≫ 10 ^{− 13} eV), the CP-violation sensitivity and δ _CP precision remain largely unaffected. These results establish ESSnuSB as a competitive experimental setup for probing LRF effects, complementing constraints from other neutrino sources and offering critical insights into the physics of long-range forces.

A bstract: Scalar non-standard neutrino interactions (sNSI) is a scenario where neutrinos can develop a medium dependent contribution to their mass due to a new scalar mediator. This scenario differs from the commonly discussed vector mediator case in that the oscillation effect scales with density rather than density and neutrino energy. Thus the strongest oscillation constraint comes from solar neutrinos which experience the largest density in a neutrino oscillation experiment. We derive constraints on all the sNSI parameters as well as the absolute neutrino mass scale by combining solar and reactor data and find solar neutrinos to be > 1 order of magnitude more sensitive to sNSI than terrestrial probes such as long-baseline experiments.