Assuming that the solar neutrino deficit observed in the Homestake, SAGE,
Gallex, Kamiokande and Super-Kamiokande experiments is due to the interaction
of the neutrino transition magnetic moment with the solar magnetic field, we
calculate the expected values of a number of observables to be measured by SNO.
For three model solar magnetic field profiles that produce the best fits of the
previous data we calculate the charged current event rate, the (neutral
current)/(charged current) event ratio and the charged current electron
spectrum as well as its first and second moments. We study the dependence of
the calculated observables on the choice of the magnetic field profile and on
the value of the solar hep neutrino flux. We also compare our results with
those obtained assuming that the solar neutrino problem is due to neutrino
oscillations in vacuum or in matter. We show that there is an overlap or
partial overlap between our predictions and those found for each of the
oscillation solutions (SMA, LMA, LOW and VO). Given the uncertainties in the
calculations and the expected uncertainties in the experimental results, the
unambiguous discrimination between the two types of solutions to the solar
neutrino problem (neutrino oscillations and magnetic moments) on the basis of
the average rates and electron spectrum distortions appears to be difficult.
The possible time dependence of the charged current signal and spectrum
distortion in the case of the magnetic moment solution therefore remains the
best hope for such a discrimination. For a hybrid solution (neutrino magnetic
moment plus flavour mixing) the smoking gun signature would be an observation
of νˉe's from the sun.Comment: LaTeX, 13 pages, 2 eps figure
