Neutrinos from a standard solar model

A detailed estimate is presented of the possible uncertainty range for the neutrino flux from a standard solar model. Using present estimated errors in the key input parameters, detailed solar models are calculated to give an uncertainty in the theoretical ν/sub e/ capture rate in both the ongoing 37Cl experiment and the proposed experiment using 71Ga. The uncertainty in capture rate is investigated by considering individual parameter variations about a mean model, by simultaneously varying several key parameters to yield upper and lower limits, and by a Monte Carlo method. It is found that with the most recent experimental value of Davis: 2.2+0.4 SNU: and the best-estimate mean model of the present work: 7.0 +- 3.0 SNU: the theoretical to experimental ratio is 3.2 +- 1.5, or 1.5 standard deviations from agreement. The prediction for 71Ga is 111 +- 13 SNU. While the mean value for the 37Cl capture rate is in good agreement with the recent calculation of Bahcell et al., the estimated uncertainty is larger than the factor of 2. The largest sources of uncertainty in these predictions are due to the range used in the 3He(α,γ)7Be cross section and to the estimate of the error range of the calculated opacities. The results are also discussed, in light of recent experimental and theoretical work on neutrino oscillations, to determine if the present situation provides any evidence of such oscillations. It is found that while there is only weak evidence in the 37Cl experiments, a discrepancy in he 71Ga experiment could be interpreted as strong evidence for neutrino oscillations