Searches for CP Violation and \pi\pi S-Wave in the Dalitz-Plot Analysis of D0 --> \pi+\pi-\pi0

TL;DR

This study analyzes the decay D0 -> pi+pi-pi0 using Dalitz-plot techniques to investigate CP violation and the pi pi S-wave contribution, providing insights into decay dynamics and CP asymmetry limits.

Contribution

It presents the first Dalitz-plot analysis of D0 -> pi+pi-pi0 with a detailed S-wave modeling and CP asymmetry measurement, highlighting differences from D+ decay.

Findings

Resonant contributions include rho pi and non-resonant components.

The pi pi S-wave contribution is limited to less than 2.5% at 95% confidence.

The measured CP asymmetry is consistent with zero within uncertainties.

Abstract

In e+e- collisions recorded using the CLEO II.V detector we have studied the Cabibbo suppressed decay of D0 -> pi+pi-pi0 with the initial flavor of the D0 tagged by the decay D*+ -> D0pi+. We use the Dalitz-plot analysis technique to measure the resonant substructure in this final state and observe \rho\pi and non-resonant contributions by fitting for their amplitudes and relative phases. We describe the pipi S-wave with a K-matrix formalism and limit this contribution to the rate to be < 2.5% @95% confidence level, in contrast to the large rate observed in D+ -> pi+pi-pi+ decay. Using the amplitudes and phases from this analysis, we calculate an integrated CP asymmetry of 0.01^{+0.09}_{-0.07} +/- 0.05.