Statistical analysis of neutrino events from SN1987A neutrino burst: estimation of the electron antineutrino mass

The method of the statistical sample moments was used for the analysis of neutrino events from SN1987A burst in Cherenkov detectors. In particular the coefficients of correlation $Q(E,t)$ between the energies $E$ of electron antineutrinos ${\bar{\nu }}_e$ emitted by star and the ejection instants $t$ of ${\bar{\nu }}_e$ for neutrino events recorded by Cherenkov water detectors of KII and IMB collaborations were calculated. $Q(E,t)$ values depend on the assumed mass of ${\bar{\nu }}_e$. Modern model of the gravitational stellar core collapse with an accretion phase predicts the low level of such correlation $<Q(E,t)>$ averaged with respect to neutrino burst. On condition that empirical $Q(E,t)$ values equal the theoretical model quantities $<Q(E,t)>$ one can obtain $22\pm 10eV\mathrm{/}{c}^2$ as an estimate of the nonzero ${\bar{\nu }}_e$ mass. The error of this estimate implies that ${\bar{\nu }}_e$ mass less than $2eV\mathrm{/}{c}^2$ is unlikely. The laboratry data of the tritium $\beta$-decay agree adequately with the presented astrophysical estimate provided that the anomalous structure near the end point of $\beta$-spectrum is taken into account.