Abstract
We have studied radiative pion decays in three broad kinematic regions using the PIBETA detector and a stopped pion beam. Based on Dalitz distributions of 41 601 events we have evaluated absolute branching ratios in the three regions. Minimum fits to the integral and differential distributions result in the axial-to-vector weak form factor ratio of , or with . However, deviations from standard model predictions in the high-–low- kinematic region indicate the need for further theoretical and experimental work.
- Received 17 December 2003
DOI:https://doi.org/10.1103/PhysRevLett.93.181804
©2004 American Physical Society