Search for Low-Energy Signals from Fast Radio Bursts with the Borexino Detector

TL;DR

This study searched for neutrino signals associated with fast radio bursts using the Borexino detector, setting new upper limits on neutrino fluences in the 0.5-50 MeV range without detecting any significant signals.

Contribution

It provides the first comprehensive search for low-energy neutrinos from FRBs with Borexino and establishes the most stringent upper limits on such neutrino fluences.

Findings

No significant neutrino excess detected.

Set the strongest upper limits on FRB-associated neutrino fluences.

Analyzed multiple neutrino spectra, including monoenergetic and supernova-like.

Abstract

The search for neutrino events in correlation with several of the most intense fast radio bursts (FRBs) has been performed using the Borexino data. We have searched for signals with visible energies above $250$~keV within a time window of $\pm$1000~s corresponding to the detection time of a particular FRB. We also applied an alternative approach based on searching for specific shapes of neutrino-electron scattering spectra in the full exposure spectrum of the Borexino detector. In particular, two incoming neutrino spectra were considered: the monoenergetic line and the spectrum expected from supernovae. The same spectra were considered for electron antineutrinos detected through the inverse beta-decay reaction. No statistically significant excess over the background was observed. As a result, the strongest upper limits on FRB-associated neutrino fluences of all flavors have been obtained in the $0.5 - 50$~MeV neutrino energy range.