Amplitude analysis of the decays and *

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.