Sterile neutrinos in tau lepton decays

Abstract

We study possible contributions of heavy sterile neutrinos $\hat{I}{½}_h$ to the decays $\ddot{I}{„}^{-}\to e^{\pm }(\hat{I}{¼}^{\pm })\ddot{I}{€}^{\mp }\ddot{I}{€}^{-}$. From the experimental upper bounds on their rates we derive new constraints on the $\hat{I}{½}_h-\hat{I}{½}_{\ddot{I}}„$ mixing in the mass region $140.5MeV\le m_{\hat{I}{½}_h}\le 1637$ MeV. We discuss cosmological and astrophysical status of $\hat{I}{½}_h$ in this mass region and compare our constraints with those recently derived by the NOMAD collaboration.

17 pages, 2 figures