Abstract
We present a new determination of the parity of the neutral pion via the double Dalitz decay . Our sample, which consists of 30 511 candidate decays, was collected from decays in flight at the KTeV-E799 experiment at Fermi National Accelerator Laboratory. We confirm the negative parity and place a limit on scalar contributions to the decay amplitude of less than 3.3% assuming conservation. The form factor is well described by a momentum-dependent model with a slope parameter fit to the final state phase-space distribution. Additionally, we have measured the branching ratio of this mode to be .
- Received 15 February 2008
DOI:https://doi.org/10.1103/PhysRevLett.100.182001
©2008 American Physical Society