Massive Dirac neutrinos from a new extension of the Standard Model
M. A. De Andrade, C. Neves, E. V. Corrêa Silva
TL;DR
This work presents a SM extension with Dirac neutrinos implemented via a twisted neutrino sector, where neutrino masses arise from a nontrivial diagonalization of a Hermitian kinetic matrix $K$ built from quark masses and a Hermitian mass matrix $M$ built from charged-lepton masses and PMNS parameters. A nonunitary transformation $\Omega$ connects the twisted and mass bases, yielding a diagonal neutrino mass matrix $m_\nu$ that reproduces the observed mass splittings when combined with a neutrino scaling parameter $\alpha_\nu$ and the PMNS matrix $U$. Using current oscillation data, the authors determine $\delta_{CP}$ and $\alpha_\nu$ that fit $\Delta m^2_{21}$ and $\Delta m^2_{31}$, predicting explicit mass eigenvalues $(m_1,m_2,m_3)$ for normal ordering and flavor-projected masses within experimental bounds; inverted ordering is disfavored. The approach unifies neutrino mass generation with the known quark and lepton masses, reduces the flavor-parameter count, and opens avenues for embedding in a GUT such as $SO(10)$ to derive $\alpha_\nu$ from fundamental symmetry breaking.
Abstract
A new approach for deriving neutrino masses from the known masses of quarks, charged leptons, and the parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix is proposed. This framework is based on the simultaneous diagonalization of the kinetic and mass terms in an extension of the Standard Model (SM) with massive Dirac neutrinos. Numerical results for the neutrino masses are obtained, which are consistent with experimental data through a new scaling parameter, $\anu$, introduced to adjust the mass splittings $Δm^2_{21}$ and $Δm^2_{31}$ in order to reach their precise experimental values, thereby reducing the number of flavor parameters in this SM extension. The proposed framework connects neutrino mass generation to the known masses of quarks and charged leptons, offering a unified perspective on the matter sector of the SM.