On mixing angles and magnetic moment of heavy tau neutrino

Abstract

If the magnetic moment of unstable tau neutrinos with the mass of $O$(MeV) is in the region of $10^{-8}{\mu }_B\lesssim {\mu }_{{\nu }_{\tau }}\lesssim 10^{-6}{\mu }_B$, it is compatible with the present experimental and cosmological bounds. It is pointed out here, that if the tau neutrino has such a large magnetic moment and can oscillate into a neutrino of another flavour the results from $\nu e$ scattering experiment at LAMPF constrain the tau neutrino mixing angles to $si{n}^{2}2{\theta }_{e\tau }\lesssim 2\times 10^{-6}-2\times 10^{-2}$ and $si{n}^{2}2{\theta }_{\mu \tau }\lesssim 10^{-6}-10^{-2}$ depending on the magnetic moment value in the allowed region.

Comments: 5 pages, LaTex