Precision Study of eta ' -> gamma pi(+) pi(-) Decay Dynamics

Abstract

Using a low background data sample of 9.7×105 J/?????, ?????+?- events, which are 2 orders of magnitude larger than those from the previous experiments, recorded with the BESIII detector at BEPCII, the decay dynamics of ?????+?- are studied with both model-dependent and model-independent approaches. The contributions of ? and the ?(770)-? interference are observed for the first time in the decays ?????+?- in both approaches. Additionally, a contribution from the box anomaly or the ?(1450) resonance is required in the model-dependent approach, while the process specific part of the decay amplitude is determined in the model-independent approach. © 2018 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.