Time-dependent Dalitz Plot Measurement of CP Parameters in B0 --> Ks Pi+ Pi- Decays

TL;DR

This paper reports a detailed time-dependent Dalitz plot analysis of CP violation in B0 decays to Ks Pi+ Pi-, using a large dataset from the Belle experiment, providing insights into CP violation parameters and decay dynamics.

Contribution

It introduces a novel time-dependent Dalitz plot analysis method for B0 decays, measuring CP violation parameters with high precision and exploring phase differences relevant for CKM angle phi3.

Findings

Two solutions fit the data well, with one favored by external data.

No evidence of direct CP violation in specific decay modes.

Measurements of mixing-induced CP violation are consistent with b --> c cbar s decays.

Abstract

We present a time-dependent Dalitz plot measurement of CP violation parameters in B0 --> Ks Pi+ Pi- decays. These results are obtained from a large data sample that contains 657 million BBbar pairs collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. For the CP violation parameters, we obtain two consistent solutions that describe the data well. The first of these solutions may be preferred by external information from other measurements. There is no evidence for direct CP violation in B0 --> rho0(770) Ks, B0 --> f0(980) Ks and B0 --> K*+(892) Pi-, while measurements of mixing-induced CP violation in B0 --> rho0(770) Ks, B0 --> f0(980) Ks decays are consistent with that of b --> c cbar s decays. We also measured the phase difference between B0 --> K*+(892) Pi- and B0B --> K*-(892) Pi+ which may be used to extract phi3.