Sterile neutrinos in tau lepton decays

Abstract

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

Comments: 17 pages, 2 figures