Reanalysis of the GALLEX solar neutrino flux and source experiments

TL;DR

This paper reanalyzes GALLEX solar neutrino data using new technical insights, resulting in a more accurate flux measurement that is slightly lower than previous estimates, with reduced uncertainty.

Contribution

It provides a retrospective update of GALLEX results incorporating new calibration data and advanced analysis techniques, improving the accuracy of solar neutrino flux measurements.

Findings

GALLEX flux is 5.3% lower than previous estimate

Reduced error margin in neutrino flux measurement

Reanalysis of source experiments confirms updated flux values

Abstract

After the completion of the gallium solar neutrino experiments at the Laboratori Nazionali del Gran Sasso (GALLEX}: 1991-1997; GNO: 1998-2003) we have retrospectively updated the GALLEX results with the help of new technical data that were impossible to acquire for principle reasons before the completion of the low rate measurement phase (that is, before the end of the GNO solar runs). Subsequent high rate experiments have allowed the calibration of absolute internal counter efficiencies and of an advanced pulse shape analysis for counter background discrimination. The updated overall result for GALLEX (only) is (73.4 +7.1 -7.3) SNU. This is 5.3% below the old value of (77.5 + 7.5 -7.8) SNU (PLB 447 (1999) 127-133) with a substantially reduced error. A similar reduction is obtained from the reanalysis of the 51Cr neutrino source experiments of 1994/1995.