Constraints on the Physical Association between ICECAT1 Neutrinos and Fast Radio Bursts Using the Second CHIME/FRB Catalogue

TL;DR

This study searches for neutrino signals associated with fast radio bursts using the latest CHIME/FRB and IceCube data, finding no significant association but setting the most stringent limits to date on neutrino emission from FRBs.

Contribution

It provides the first comprehensive, statistically rigorous search for FRB-neutrino associations and establishes new upper limits that challenge some models of hadronic energy dissipation in FRBs.

Findings

No significant FRB-neutrino associations detected.

Established upper limits on neutrino-to-radio luminosity ratio, improving previous constraints.

Limits begin to challenge models with highly efficient hadronic energy dissipation.

Abstract

We present a search for neutrino counterparts to fast radio bursts (FRBs) using temporal and spatial cross-matching between the Second CHIME/FRB catalogue and the IceCube high-energy alert-track catalogue ICECAT1. Because current FRB--neutrino models do not provide a unique consensus on emission ordering, our primary significance test adopts a two-sided, order-agnostic temporal hypothesis. The analysis accounts for declination-dependent CHIME/FRB exposure and the look-elsewhere effect across multiple trials. No statistically significant FRB--neutrino association is found. The most significant pair is FRB\,20190630C--IC\,190629A, with a post-trial probability of $p=0.076$ ($1.43\sigma$), consistent with a chance coincidence. Within our statistical framework, a detectable physical association would require a time offset shorter than $\sim256$~s at $3\sigma$ or $\sim63$~ms at $5\sigma$. Using a population-level stacking analysis, we derive 90\% upper limits on the neutrino-to-radio luminosity ratio of FRBs, $\xi \lesssim 10^{8}-10^{11}$ for neutrino power-law spectral indices $\gamma=1.0-3.0$. These limits improve upon previous constraints by approximately two orders of magnitude and represent the most stringent bounds from FRB--neutrino coincidence searches to date. Although the current limits remain above the predictions of most magnetar-based models, they begin to constrain scenarios involving exceptionally efficient hadronic energy dissipation.