Branching ratios for the beta decay of Na-21
Additional Document Info
We have measured the beta-decay branching ratio for the transition from Na21 to the first excited state of Ne21. A recently published test of the standard model, which was based on a measurement of the - correlation in the decay of Na21, depended on this branching ratio. However, until now only relatively imprecise (and, in some cases, contradictory) values existed for it. Our new result, 4.74(4)%, reduces but does not remove the reported discrepancy with the standard model. 2006 The American Physical Society.