The IceCube Neutrino Observatory, the Pierre Auger Observatory and the Telescope Array: Joint Contribution to the 34th International Cosmic Ray Conference (ICRC 2015)

TL;DR

This paper reports on joint analyses of ultra-high energy cosmic rays and high-energy neutrinos to identify potential correlations, using multiple statistical methods and considering magnetic deflections, to enhance understanding of cosmic ray and neutrino origins.

Contribution

It presents the first combined analysis of UHECRs and neutrinos from IceCube, Pierre Auger, and Telescope Array, employing cross-correlation and likelihood methods to search for source correlations.

Findings

No significant correlations found between UHECRs and neutrinos.

The analysis constrains possible source models for ultra-high energy particles.

Magnetic deflections are accounted for in the correlation searches.

Abstract

We have conducted three searches for correlations between ultra-high energy cosmic rays detected by the Telescope Array and the Pierre Auger Observatory, and high-energy neutrino candidate events from IceCube. Two cross-correlation analyses with UHECRs are done: one with 39 cascades from the IceCube `high-energy starting events' sample and the other with 16 high-energy `track events'. The angular separation between the arrival directions of neutrinos and UHECRs is scanned over. The same events are also used in a separate search using a maximum likelihood approach, after the neutrino arrival directions are stacked. To estimate the significance we assume UHECR magnetic deflections to be inversely proportional to their energy, with values $3^\circ$, $6^\circ$ and $9^\circ$ at 100 EeV to allow for the uncertainties on the magnetic field strength and UHECR charge. A similar analysis is performed on stacked UHECR arrival directions and the IceCube sample of through-going muon track events which were optimized for neutrino point-source searches.