Determination of the D0 -> K-pi+pi0 and D0 -> K-pi+pi+pi- Coherence Factors and Average Strong-Phase Differences Using Quantum-Correlated Measurements

TL;DR

This paper measures coherence factors and strong-phase differences for specific D0 decays using quantum-correlated data, improving parameters crucial for determining the CKM angle gamma in B decays.

Contribution

It provides the first measurements of these parameters for D0->K-pi+pi0 and D0->K-pi+pi+pi- decays using quantum-correlated D meson pairs.

Findings

Significant coherence in D0->K-pi+pi0 decay.

Lower coherence observed in D0->K-pi+pi+pi- decay.

Small improvement in D-meson parameter knowledge.

Abstract

The first measurements of the coherence factors (R_Kpipi0 and R_K3pi) and the average strong-phase differences (delta_D^Kpipi0 and delta_D^K3pi) for D0->K-pi+pi0 and D0->K-pi+pi+pi- are presented. These parameters can be used to improve the determination of the unitarity triangle angle gamma in B^- -> DK^- decays, where D is a D^0 or Dbar^0 meson decaying to the same final state. The measurements are made using quantum-correlated, fully-reconstructed D^0Dbar^0 pairs produced in e+e- collisions at the psi(3770) resonance. The measured values are: R_Kpipi0=0.84+/-0.07, delta_D^Kpipi0=(227+14-17) deg, $R_K3pi=0.33+0.20-0.23, and delta_D^K3pi=(114+26-23) deg. These results indicate significant coherence in the decay D0->K-pi+pi0, whereas lower coherence is observed in the decay D0->K-pi+pi+pi-. The analysis also results in a small improvement in the knowledge of other D-meson parameters, in particular the strong-phase difference for D0->K-pi+, delta_D^Kpi, and the mixing parameter, y.