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Main Authors: Bozza, Riccardo Maria, di Risi, Vigilante, Oliviero, Veronica, Ricciardi, Giulia, Vissani, Francesco
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2605.06401
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author Bozza, Riccardo Maria
di Risi, Vigilante
Oliviero, Veronica
Ricciardi, Giulia
Vissani, Francesco
author_facet Bozza, Riccardo Maria
di Risi, Vigilante
Oliviero, Veronica
Ricciardi, Giulia
Vissani, Francesco
contents The interpretation of the SN1987A neutrino data continues to be hindered by significant absolute timing uncertainties and a well-known tension in the angular distributions. We perform a quantitative, high-precision alignment of the Kamiokande-II and Baksan data with the IMB clock, using for the first time the relative time offset (RTO) and reducing the temporal uncertainty by two orders of magnitude to the sub-second level. The chi-square analysis shows that Baksan's absolute timestamps require an advancement of 30.4 s, while those of Kamiokande-II require a delay of about 6.4 s. The knowledge of the unified timeline provides a necessary and rigorous basis for testing whether the first Kamiokande-II event arose from the neutronization burst - a possibility motivated by its angular properties. Our analysis favors an accretion phase electron anti-neutrino origin over a neutronization-burst origin, with a likelihood ratio of 3-6, depending on the specific MSW oscillation scenario. This result corroborates the standard interpretation - that only inverse beta decay events were detected. Our framework yields the most stringent constraints to date on the SN1987A chronology and establishes a precision benchmark for future Galactic supernova observations.
format Preprint
id arxiv_https___arxiv_org_abs_2605_06401
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle The temporal distribution of SN1987A neutrino events
Bozza, Riccardo Maria
di Risi, Vigilante
Oliviero, Veronica
Ricciardi, Giulia
Vissani, Francesco
High Energy Physics - Phenomenology
High Energy Astrophysical Phenomena
High Energy Physics - Experiment
The interpretation of the SN1987A neutrino data continues to be hindered by significant absolute timing uncertainties and a well-known tension in the angular distributions. We perform a quantitative, high-precision alignment of the Kamiokande-II and Baksan data with the IMB clock, using for the first time the relative time offset (RTO) and reducing the temporal uncertainty by two orders of magnitude to the sub-second level. The chi-square analysis shows that Baksan's absolute timestamps require an advancement of 30.4 s, while those of Kamiokande-II require a delay of about 6.4 s. The knowledge of the unified timeline provides a necessary and rigorous basis for testing whether the first Kamiokande-II event arose from the neutronization burst - a possibility motivated by its angular properties. Our analysis favors an accretion phase electron anti-neutrino origin over a neutronization-burst origin, with a likelihood ratio of 3-6, depending on the specific MSW oscillation scenario. This result corroborates the standard interpretation - that only inverse beta decay events were detected. Our framework yields the most stringent constraints to date on the SN1987A chronology and establishes a precision benchmark for future Galactic supernova observations.
title The temporal distribution of SN1987A neutrino events
topic High Energy Physics - Phenomenology
High Energy Astrophysical Phenomena
High Energy Physics - Experiment
url https://arxiv.org/abs/2605.06401