Abstract
Based on a sample of events collected with the BESIII detector, the matrix elements for the decays and are determined using 351,016 and 56,249 events with background levels less than 1%. Two commonly used representations are used to describe the Dalitz plot density. We find that an assumption of a linear amplitude does not describe the data well. A small deviation of the obtained matrix elements between and is probably caused by the mass difference between charged and neutral pions or radiative corrections. No cusp structure in is observed.
- Received 14 September 2017
DOI:https://doi.org/10.1103/PhysRevD.97.012003
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Published by the American Physical Society