New determination of the D 0 → K ? π + π 0 and D 0 → K ? π + π + π ? coherence factors and average strong-phase differences

摘要

Measurements of the coherence factors (RKππ0andRK3π) and the average strong-phase differences (δDKππ0andδDK3π) for the decaysD0→K?π+π0andD0→K?π+π+π?are presented. These parameters are important inputs to the determination of the unitarity triangle angleγinB?→DK?decays, whereDdesignates aD0orDˉ0meson decaying to a common final state. The measurements are made using quantum correlatedDDˉdecays collected by the CLEO-c experiment at theψ(3770)resonance, and augment a previously published analysis by the inclusion of new events in which the signal decay is tagged by the modeD→KS0π+π?. The measurements also benefit from improved knowledge of external inputs, namely theD0Dˉ0mixing parameters,rDKπand severalD-meson branching fractions. The measured values areRKππ0=0.82±0.07,δDKππ0=(164?14+20)°,RK3π=0.32?0.28+0.20andδDK3π=(225?78+21)°. Consideration is given to how these measurements can be improved further by using the larger quantum-correlated data set collected by BESIII.