Ultra-high neutrino fluxes as a probe for non-standard physics

Understand

We examine how light neutrinos coming from distant active galactic nuclei (AGN) and similar high energy sources may be used as tools to probe non-standard physics.

• In particular we discuss how studying the energy spectra of each neutrino flavour coming from such distant sources and their distortion relative to each other may serve as pointers to exotic physics such as neutrino decay, Lorentz symmetry violation, pseudo-Dirac effects, CP and CPT violation and quantum decoherence.
• This allows us to probe hitherto unexplored ranges of parameters for the above cases, for example lifetimes in the range $ 10^{-3}-10^{4} $ s/eV for the case of neutrino decay.
• We show that standard neutrino oscillations ensure that the different flavours arrive at the earth with similar shapes even if their flavour spectra at source may differ strongly in both shape and magnitude.