Neutrino Oscillations Induced by Two-loop Radiative Mechanism

Abstract

Two-loop radiative mechanism, when combined with an U(1)_{L'} symmetry generated by L_e-L_μ-L_τ(=L'), is shown to provide an estimate of Δm^2_{\odot}/Δm^2_{atm} $\sim$ εm_e/m_τ, where εmeasures the U(1)_{L'}-breaking. Since Δm^2_{atm} $\sim 3.5x10^{-3} eV^2, we find that Δm^2_{\odot} $\sim$ εx10^{-6} eV^2, which will fall into the allowed region of the LOW solution to the solar neutrino problem for ε$\sim$ 0.1.