The anisotropy of inverse beta decay and antineutrino detection

Abstract

The anisotropy of the positrons emitted in the reaction $\bar{\hat{I}}{½}_e+p\to n+e^{+}$ has to be taken into account for extracting an antineutrino signal in Superkamiokande. For the Sun, this effect allows a sensitivity to $\hat{I}{½}_e\to \bar{\hat{I}}{½}_e$ transition probability at the 3% level already with the statistics collected in the first hundred days. For a supernova in the Galaxy, the effect is crucial for extracting the correct ratio of $\hat{I}½-e$ to $\bar{\hat{I}}{½}_e-p$ events.

3 pages including 2 figures, LaTex file, espcrc2.sty is needed; to appear in Nucl. Phys. B Proc. Suppl., Proceedings of TAUP97 conference, Laboratori Nazionali del Gran Sasso, September 1997