12/10 Observation of an Unusual Upward-going Cosmic-ray-like Event in the Third Flight of ANITA

Time: 1:20pm, December 10 (Thursday)

Title: Observation of an Unusual Upward-going Cosmic-ray-like Event in the Third Flight of ANITA

Speaker: Prof. TsungChe Liu
(Electrophysics Department, National Chiao Tung University)

Place: Science Building III 1F SC110

Abstract:

We report on an upward traveling, radio-detected cosmic-ray-like impulsive event with characteristics closely matching an extensive air shower. This event,
observed in the third flight of the Antarctic Impulsive Transient Antenna (ANITA), a NASA-sponsored long-duration balloon payload, is consistent with a similar event reported in a previous flight.
These events may be produced by the atmospheric decay of an upward-propagating τ-lepton produced by a ντ interaction, although their relatively steep arrival angles create tension with the standard model (SM) neutrino cross section.
Each of the two events have a posteriori background estimates of <∼ 10^{−2} events.
If these are generated by τ-lepton decay, then either the charged-current ντ cross section is suppressed at EeV energies, or the events arise at moments
when the peak flux of a transient neutrino source was much larger than the typical expected cosmogenic background neutrinos.

https://arxiv.org/pdf/1803.05088.pdf