  A significant decay branch of 8B to the ground state of 8Be would extend the
solar neutrino spectrum to higher energies than anticipated in the standard
solar models. These high-energy neutrinos would affect current neutrino
oscillation results and also would be a background to measurements of the hep
process. We have measured the delayed alpha particles from the decay of 8B,
with the goal of observing the two 46-keV alpha particles arising from the
ground-state decay. The 8B was produced using an in-flight radioactive beam
technique. It was implanted in a silicon PIN-diode detector that was capable of
identifying the alpha-particles from the 8Be ground state. From this
measurement we find an upper limit (at 90% confidence level) of 7.3 x 10^{-5}
for the branching ratio to the ground state. In addition to describing this
measurement, we present a theoretical calculation for this branching ratio.
