Lightest Nuclei in UHECR versus Tau Neutrino Astronomy

TL;DR

This paper explores how the composition of ultra-high-energy cosmic rays (UHECR), especially light nuclei like helium, affects neutrino production and detection, impacting tau neutrino astronomy.

Contribution

It analyzes the influence of light nuclei in UHECR on neutrino signals and their implications for tau neutrino astronomy, considering nuclear fragmentation and GZK suppression effects.

Findings

Light nuclei explain the absence of Virgo signals and event clustering around Cen-A.

UHECR helium nuclei produce low-energy neutrinos via nuclear fragmentation.

Both light and heavy nuclei UHECRs significantly impact expected GZK neutrino signals.

Abstract

UHECR may be either nucleons or nuclei; in the latter case the Lightest Nuclei, as He, Li, Be, explains at best the absence of Virgo signals and the crowding of events around Cen-A bent by galactic magnetic fields. This model fit the observed nuclear mass composition discovered in AUGER. However UHECR nucleons above GZK produce EeV neutrinos while Heavy Nuclei, as Fe UHECR do not produce much. UHECR He nuclei at few tens EeV suffer nuclear fragmentation (producing low energetic neutrino at tens PeVs) but it suffer anyway photo-pion GZK suppression (leading to EeV neutrinos) once above one-few 10^{20} eV. Both these cosmogenic UHE secondary neutrinos signals may influence usual predicted GZK Tau Neutrino Astronomy in significant and detectable way; the role of resonant antineutrino electron-electron leading to Tau air-shower may also rise.