Electron-neutrino Majorana mass and solar neutrino oscillations

Assuming the Majorana masses of νe and the linear combination cντ−sνμ to be equal from their couplings to a heavy scalar triplet ξ, I show that their radiative splitting is given by Δm2/mν2=(3c2/4π2)(GF/2)mτ2ln(mξ2/mW2). This is applicable to the small-angle matter-enhanced oscillation solution of the solar neutrino deficit and restricts mν to be between 0.20 and 0.36 eV if c2=0.7 and mξ=1014 GeV.