Observing EeV neutrinos through the Earth: GZK and the anomalous ANITA events

Understand

Tau neutrinos are unique cosmic messengers, especially at extreme energies.

• When they undergo a charged-current interaction, the short lifetime of the produced tau gives rise to secondary tau neutrinos that carry a significant fraction of the primary neutrino energy.
• This effect, known as tau neutrino regeneration, has not been applied to its full potential in current generation neutrino experiments.
• In this work, we present an updated calculation of tau neutrino regeneration, and explore its implications for two scenarios: the recent anomalous ANITA events and the cosmogenic neutrino flux.