The anisotropy of inverse beta decay and antineutrino detection

Abstract

The anisotropy of the positrons emitted in the reaction ${\bar{\nu }}_e+p\to n+e^{+}$ has to be taken into account for extracting an antineutrino signal in Superkamiokande. For the Sun, this effect allows a sensitivity to ${\nu }_e\to {\bar{\nu }}_e$ 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 $\nu -e$ to ${\bar{\nu }}_e-p$ events.

Comments: 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