The Sensitivity of PUEO to Cosmogenic Neutrinos and Exotic Physics Scenarios

TL;DR

PUEO, a balloon-based observatory, will significantly enhance detection sensitivity for ultrahigh-energy neutrinos, enabling new insights into cosmic-ray composition, dark matter decay, and cosmic strings.

Contribution

This work evaluates PUEO's potential to detect cosmogenic neutrinos and constrain exotic physics scenarios, highlighting its unprecedented sensitivity in the 1-1000 EeV range.

Findings

PUEO can constrain the proton fraction of ultrahigh-energy cosmic rays.

It will set the strongest neutrino constraints above 10^19 eV.

PUEO can probe models of cosmic strings effectively.

Abstract

Several observatories designed to detect ultrahigh-energy neutrinos are planned for the next decade. The most imminent of these is the Payload for Ultrahigh Energy Observations (PUEO), a long-duration balloon-based experiment that will provide unprecedented sensitivity to neutrinos with energies in the range of ~ 1 - 1000 EeV. In this work, we assess the scientific reach of PUEO. In particular, we evaluate the sensitivity of this observatory to cosmogenic neutrinos and, in turn, to the proton fraction of the ultrahigh-energy cosmic-ray spectrum. We also consider the potential of PUEO to probe scenarios in which neutrinos are produced through the decays of ultraheavy dark matter particles or are radiated from cosmic strings. We find that PUEO will be able to constrain the proton composition of ultrahigh-energy cosmic rays in scenarios that feature very strong source evolution and in which protons are accelerated to extremely high energies. Although gamma-ray observations are generally more sensitive to decaying particles than neutrino observations, PUEO is expected to set the strongest neutrino-detector constraints above 10^19 eV. PUEO will also provide the strongest constraints on some models of cosmic strings.