The LSND Experiment and the Zee Model

Abstract

A recent experiment LSND at Los Alamos has provided\cite{1} an indication of ${\overline{\nu }}_{\mu }-{\overline{\nu }}_e$ oscillations with $\Delta m^2$ of order 1ev${}^2$ or greater and ${\sin }^{2}2{\theta }_{e\mu }$ between $2\times 10^{-3}$ and $10^2$. Such a value of $\Delta m^2$ for ${\nu }_{\mu }-{\nu }_e$ oscillations was not expected in the standard see-saw model\cite{2} suggested by SO(10) with a large mass hierarchy because it leads to too large a value of $m({\nu }_{\tau })$ to fit cosmological constraints. Furthermore within that model the LSND result is inconsistent with the indications of oscillations from both atmospheric neutrinos\cite{3} and solar neutrinos.\cite{4}

3 pages, latex, no figures