Implications of the GALLEX Source Experiment for the Solar Neutrino Problem

We argue that, prior to the recent GALLEX 51Cr source experiment, the excited state contributions to the 71Ga capture cross section for 51Cr and 7Be neutrinos were poorly constrained, despite forward-angle (p,n) measurements. We describe the origin of the uncertainties and estimate their extent. We explore the implications of the source experiment for solar neutrino capture in light of these uncertainties. A reanalysis of the 7Be and 8B flux constraints and MSW solutions of the solar neutrino puzzle is presented. Recently the GALLEX collaboration reported the first results of a Cr neutrino source experiment [1]. The collaboration stressed the importance of this measurement as a test of experimental procedures, including the overall recovery efficiency of the product Ge. This test is in addition to the run-by-run checks on the chemical extraction efficiency that have been performed by introducing Ge carrier. These have consistently indicated Ge yields of about 99% [2]. The significance of the source experiment is that it tests the recovery of Ge under production conditions almost precisely mimicking those of solar neutrinos. For instance,