How Accurately Do We Know the Formation of Solar 8B?

Abstract

The large value of \S17 = 22.1 \xpm 0.6 eV-b, reported by the Seattle group, suggests a larger total \b8 solar neutrino flux. Together with the two high precision values quoted for \s34 it is either 20% or 9% larger than measured by SNO. While the accuracy of the Standard Solar Model has recently been revisited, precise nuclear inputs are still relevant, but a detailed examination of current data on \xs17 (as opposed to an examination of \S17 only) excludes quoting \S17 with sufficiently small uncertainty. In contrast to suggestions that \S17 is now known with the (impressive) accuracy of \xpm 3%, the exact value of \S17 is dependent on the choice of the data and the choice of theory used for extrapolation. In addition recent high precision results (including the Seattle data) on \xs17 which are in good agreement, still differ on the measured slopes, as does the theory, precluding an accurate extrapolation to zero energy of the consistent data. Using a common extrapolation of only the consistent high precision data, suggests a value of \S17 = 21.2 \xpm 0.5 eV-b, but a value equal to or smaller than 19.0 eV-b can not be excluded due to the uncertainty in the extrapolation, leading to an additional error of $^{+0.0}_{-3.0}$ eV-b. A proposal to remedy this situation is discussed.