Electron capture on 8B nuclei and Superkamiokande results

The energy spectrum of recoil electrons from solar neutrino scattering, as observed by Superkamiokande, is deformed with respect to that expected from SSM calculations. We considered nu - e scattering from neutrinos produced by the electron-capture on B-8 nuclei, e(-)+B-8 --> Be-8* + nu(e), as a possible explanation of the spectral deformation. A flux Phi(eB) similar or equal to 10(4) cm(-2) s(-1) could account for Superkamiokande solar neutrino data. However this explanation is untenable, since the theoretical prediction, Phi(eB) = (1.3 +/- 0.2) cm(-2) s(-1), is smaller by four orders of magnitude. (C) 1999 Published by Elsevier Science B.V. All rights reserved.