Amplitude analysis of the decays and * *Supported in part by the National Key R&D Program of China (2020YFA0406300, 2020YFA0406400); the National Natural Science Foundation of China (NSFC) (11625523, 11635010, 11735014, 11835012, 11935015, 11935016, 11935018, 11961141012, 12025502, 12035009, 12035013, 12061131003, 12105276, 12122509, 12192260, 12192261, 12192262, 12192263, 12192264, 12192265, 12221005, 12225509, 12235017); the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility

Abstract

Using annihilation data corresponding to an integrated luminosity of 2.93 taken at the center-of-mass energy GeV with the BESIII detector, a joint amplitude analysis is performed on the decays and (non-η). The fit fractions of individual components are obtained, and large interferences among the dominant components of the decays , , , and are observed in both channels. With the obtained amplitude model, the -even fractions of and (non-η) are determined to be % and %, respectively. The branching fractions of and (non-η) are measured to be % and %, respectively. The amplitude analysis provides an important model for the binning strategy in measuring the strong phase parameters of when used to determine the CKM angle via the decay.