Neutrino masses,leptonic flavor mixing,and muon(g−2)in the seesaw model with the U(1)Lμ-Lrgauge symmetry

The latest measurements of the anomalous muon magnetic moment a_μ≡(g_μ-2)/2show a 4:2σdiscrepancy between the theoretical prediction of the Standard Model and the experimental observations.To account for such a discrepancy,we consider a possible extension of the type-(I+II)seesaw model for neutrino mass generation with a gauged L_μ-L_rsymmetry.By explicitly constructing an economical model with only one extra scalar singlet,we demonstrate that the gauge symmetry U(1)L_μ-L_rand its spontaneous breaking are crucial not only for explaining the muon result but also for generating the neutrino masses and leptonic flavor mixing.Various phenomenological implications and experimental constraints on the model parameters are also discussed.