Singlet Interacting Neutrinos in the Extended Zee Model and Solar Neutrino Transformation

We study the impact of Standard Model singlet neutrinos on neutrino flavor transformation. We focus on an extension of the Zee model which includes singlet neutrinos, and find that the best limits on the interactions of the singlet neutrinos come from astrophysical phenomena. Singlet neutrino-electron scattering will impact both the mattter enhanced flavor transformation potential as well as detector cross sections. If electron neutrino - singlet neutrino oscillations are responsible for the solar neutrino anomaly, then the limit on the singlet neutrino interaction strength is of order of the weak interaction scale. Zee model modification of nu_tau - e scattering also impacts solar neutrino transformation, although this interaction is more tightly constrained.