Tau neutrinos from active galactic nuclei

Abstract

We study the appearance of ${\nu }_{\tau }$ from active galactic nuclei (AGN) through neutrino spin-flip. We consider two situations: i) Spin (flavour)-precession in a reasonable strength of magnetic field in AGN, $B_{AGN}$ ii) Adiabatically resonant conversions caused by an interplay of $B_{AGN}$ and the violation of equivalence principle. Observational consequences for both situations are discussed.

Comments: 6 pages, Latex (uses espcrc2), 1 figure included with epsf, talk presented at Fifth International Workshop on Tau Lepton Physics (TAU98), Santander, Spain, 14-17 September, 1998 [to appear in its proceedings in Nucl. Phys. B (Proc. Suppl.)]