The 71Ga(3He,t) reaction and the low-energy neutrino response

Abstract A 71 Ga( 3 He,  t ) 71 Ge charge-exchange experiment was performed to extract with high precision the Gamow–Teller (GT) transition strengths to the three lowest-lying states in 71 Ge, i.e., the ground state ( 1 / 2 − ) , the 175 keV ( 5 / 2 − ) and the 500 keV ( 3 / 2 − ) excited states. These are the relevant states, which are populated via a charged-current reaction induced by neutrinos from reactor-produced 51 Cr and 37 Ar sources. A precise measurement of the GT transition strengths is an important input into the calibration of the SAGE and GALLEX solar neutrino detectors and addresses a long-standing discrepancy between the measured and evaluated capture rates from the 51 Cr and 37 Ar neutrino calibration sources, which has recently spawned new ideas about unconventional neutrino properties.