On the Tau flavor of the cosmic neutrino flux

Understand

Observation of high energy cosmic neutrinos by ICECUBE has ushered in a new era in exploring both cosmos and new physics beyond the Standard Model (SM).

• In the standard picture, although mostly $\nu_\mu$ and $\nu_e$ are produced in the source, oscillation will produce $\nu_\tau$ {\it en route}.
• Certain beyond SM scenarios, like interaction with ultralight DM can alter this picture.
• Thus, the flavor composition of the cosmic neutrino flux can open up the possibility of exploring certain beyond the SM scenarios that are inaccessible otherwise.