Exploring Neutrino Masses (<i>g</i> − 2)<i>_μ,e</i> in Type I+II Seesaw in <i>L_e</i>–<i>L_α</i>-Gauge Extended Model

Abstract

This paper aims to explore the implications of U(1)Le−Lα gauge symmetries, where α=τ,μ, in the neutrino sector through type-(I+II) seesaw mechanisms. To achieve such a hybrid framework, we include a scalar triplet and three right-handed neutrinos. The model can successfully account for the active neutrino masses, mixing angles, mass squared differences, and the CP-violating phase within the 3σ bounds of NuFit v5.2 neutrino oscillation data. The presence of a new gauge boson at the MeV scale provides an explanation for the muon and electron (g−2) within the confines of their experimental limits. Furthermore, we scrutinize the proposed models in the context of upcoming long-baseline neutrino experiments such as DUNE, P2SO, T2HK, and T2HKK. The findings reveal that P2SO and T2HK have the ability to probe both models in their 5σ-allowed oscillation parameter region, whereas DUNE and T2HKK can conclusively test only the model with U(1)Le−Lμ-symmetry within the 5σ parameter space if the true values of the oscillation parameters remain consistent with NuFit v5.2.

Keywords

• neutrino masses and mixing
• U(1) gauge extension model
• muon (g − 2)