Can the Zee Model Explain the Observed Neutrino Data?

Abstract

The eigenvalues and mixing angles in the Zee model are investigated parameter-independently. When we require |Δm^2_{12}/Δm^2_{23}| \ll 1 in order to understand the solar and atmospheric data simultaneously, the only solution is one which gives bi-maximal mixing. It is pointed out that the observed values \sin^2 2θ_{solar} \simeq 0.66 in the MSW LMA solution cannot be explained within the framework of the Zee model, because we derive a severe constraint on the value of \sin^2 2 θ_{solar}, \sin^2 2 θ_{solar} \geq 1 -(1/16)(Δm^2_{solar}/Δm^2_{atm})^2.