Amplitude Analysis of the Decays D0→π+π-π+π- and π+π-π0π0

Using e+e- annihilation data corresponding to an integrated luminosity of 2.93 fb-1 taken at the center-of-mass energy √s=3.773 GeV with the BESIII detector, a joint amplitude analysis is performed on the decays D0→π+π-π+π- and D0→π+π-π0π0(non-η). The fit fractions of individual components are obtained, and large interferences among the dominant components of the decays D0→a1(1260)π, D0→π(1300)π, D0→ρ(770)ρ(770) and D0→2(ππ)S are found in both channels. With the obtained amplitude model, the CP-even fractions of D0→π+π-π+π- and D0→π+π-π0π0(non-η) are determined to be (75.2 ± 1.1stat. ± 1.5syst.)% and (68.9 ± 1.5stat. ± 2.4syst.)%, respectively. The branching fractions of D0→π+π-π+π- and D0→π+π-π0π0(non-η) are measured to be (0.688 ± 0.010stat. ± 0.010syst.)% and (0.951 ± 0.025stat. ± 0.021syst.)%, respectively. The amplitude analysis provides an important model for binning strategy in the measurements of the strong phase parameters of D0→4π when used to determine the CKM angle γ(Φ3) via the B-→DK- decay. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.