Neutrino masses and LFV from minimal breaking of U(3)^5 and U(2)^5 flavor symmetries

TL;DR

This paper explores how minimal breaking of flavor symmetries in supersymmetry can explain neutrino masses and predict lepton flavor violation rates, aligning with recent experimental results and cosmological bounds.

Contribution

It introduces a minimal symmetry-breaking framework that links neutrino mass degeneracy, mixing angles, and LFV predictions within supersymmetric models.

Findings

Neutrino masses are nearly degenerate, near current cosmological and $0 uetaeta$ bounds.

Predicted mixing angle $s_{13} \\approx 0.16$ matches DayaBay results.

LFV branching ratios for $\\mu \\to e \\gamma$ and $\tau \\to \\mu \\gamma$ are within future experimental reach.

Abstract

We analyze neutrino masses and Lepton Flavor Violation (LFV) in charged leptons with a minimal ansatz about the breaking of the U(3)^5 flavor symmetry, consistent with the U(2)^3 breaking pattern of quark Yukawa couplings, in the context of supersymmetry. Neutrino masses are expected to be almost degenerate, close to present bounds from cosmology and $0\nu\beta\beta$ experiments. We also predict $s_{13} \approx s_{23} |V_{td}|/|V_{ts}| \approx 0.16$, in perfect agreement with the recent DayaBay result. For slepton masses below 1 TeV, barring accidental cancellations, we expect $\cB(\mu \to e \gamma) > 10^{-13}$ and $\cB(\tau \to \mu \gamma) > 10^{-9}$, within the reach of future experimental searches.