The flux of electron antineutrinos from supernova SN1987A data

TL;DR

This paper analyzes SN1987A neutrino data using an advanced model, confirming the accretion phase with high confidence and providing detailed thermodynamical insights consistent with theoretical expectations.

Contribution

It introduces a comprehensive analysis framework that incorporates arrival times, energies, and angles, confirming the accretion phase and estimating key emission parameters with improved reliability.

Findings

Accretion phase confirmed at 99% confidence level.

Neutron mass involved during accretion estimated at about 0.02 solar masses.

Cooling emission duration aligns with theoretical models.

Abstract

By adopting a state-of-the-art parameterized model of electron antineutrino emission, we have made some steps forward in the analysis of the thermodynamical properties and temporal structure of neutrino emission from core collapse SN1987A. Our analysis, unlike similar previous ones, takes into account the times, energies and angles of arrival of the detected events in a reliable framework which includes a finite ramp in the initial stage of the neutrino emission. The existence of the accretion phase is confirmed with a confidence level of about 99%, and the neutrons involved in the emission during accretion, for the first time, do not show significant tensions with expectations, being about 0.02 $M_\odot$. We determine the parameters of the cooling emission and discuss its duration, that compares well with theoretical expectations. We estimate the delay times between the first neutrino and the first event in the detectors. The goodness of fit checks, performed on the temporal, energy and angular distributions, show that the flux resulting from the best-fit analysis is compatible with the observed data.