Abstract
Background: The decays of H and He can play an important role in testing nuclear wave-function calculations and fixing low-energy constants in effective-field theory approaches. However, there exists a large discrepancy between previous measurements of the He half-life.
Purpose: Our measurement aims at resolving this long-standing discrepancy in the He half-life and providing a reliable value and Gamow-Teller matrix element for comparison with theoretical ab initio calculations.
Method: We measured the He half-life by counting the -decay electrons with two scintillator detectors operating in coincidence.
Results: The measured He half-life is ms corresponding to a relative precision of . Calculating the statistical rate function we determined the value to be s.
Conclusions: Our result resolves the previous discrepancy by providing a higher-precision result with careful analysis of potential systematic uncertainties. The result provides a reliable basis for future precision comparisons with ab initio calculations.
4 More- Received 15 June 2012
DOI:https://doi.org/10.1103/PhysRevC.86.035506
©2012 American Physical Society