Precision evaluation of the Ga71(νe,e−) solar neutrino capture rate from the (He3,t) charge-exchange reaction

A precision measurement of the Ga71(He3,t)Ge71 charge-exchange reaction was performed. By using a rather complete set of theoretical form factors to describe the cross-section angular distributions over a large angular range, the Gamow-Teller strength distribution up to the effective neutron-separation energy in Ge71 was extracted. The data and the analysis constrain the Ga71(νe,e−) solar neutrino rate in a neutrino nonoscillation scenario. For nonoscillating neutrinos we report a solar neutrino capture rate of 122.4±3.4(stat)±1.1(sys) SNU, which is lower than the presently accepted value of 132±18 SNU, though not in disagreement given the quoted errors.