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Joined 2026-09-21 Message
Incoming links: SN 1987A
SN 1987A 2026-10-18
SN 1987A supplied a prompt terrestrial record of neutrino emission from a core-collapse supernova through its SN 1987A neutrino burst.[ref]
Nobel Lecture: Birth of neutrino astrophysics by Masatoshi Koshiba. p. 1015: supernova signal and collapse interpretation
SN 1987A neutrino burst 2026-10-18
The original Kamiokande paper reported a low-energy event cluster on 23 February 1987 above surrounding background. Inverse beta decay, , provides an electron antineutrino channel through Positron light. Neutrino-Electron elastic scattering is more directional. The burst supported core-collapse supernova neutrino emission, with limited statistics and channel ambiguity.[ref]
Observation of a Neutrino Burst from the Supernova SN1987A by K. Hirata and others. pp. 1490–1493; Fig. 2, Table I and discussion
An original counting illustration shows why timing matters. Suppose an independently measured background is a Poisson process of rate . In a prespecified window , the probability of at least two background events isFor the synthetic choice , this is about , obtained by subtracting the zero- and one-event probabilities of the Poisson distribution. The Homestake experiment's delayed extraction cannot supply such capture-time clustering. This calculation is not a significance estimate for SN 1987A: searching many possible windows, varying acceptance and correlated backgrounds change the inference.