Determination of the Strong Phase in D0 -> K+pi- Using Quantum-Correlated Measurements

TL;DR

This paper measures the strong phase difference in D0 decays using quantum coherence in psi(3770) decays, providing new insights into charm mixing parameters with experimental data.

Contribution

It presents the first determination of the strong phase etween D0 nd D0bar ecays using quantum-correlated measurements at psi(3770).

Findings

Measured ost 1.03 with uncertainties.

Obtained ost 1.10 with uncertainties when including other data.

Estimated xnd elta around 4.4 0^-3 and 22 degrees, respectively.

Abstract

We exploit the quantum coherence between pair-produced D0 and D0bar in psi(3770) decays to study charm mixing, which is characterized by the parameters x and y, and to make a first determination of the relative strong phase \delta between D0 -> K+pi- and D0bar -> K+pi-. Using 281 pb^-1 of e^+e^- collision data collected with the CLEO-c detector at E_cm = 3.77 GeV, as well as branching fraction input and time-integrated measurements of R_M = (x^2+y^2)/2 and R_{WS} = Gamma(D0 -> K+pi-)/Gamma(D0bar -> K+pi-) from other experiments, we find \cos\delta = 1.03 +0.31-0.17 +- 0.06, where the uncertainties are statistical and systematic, respectively. By further including other mixing parameter measurements, we obtain an alternate measurement of \cos\delta = 1.10 +- 0.35 +- 0.07, as well as x\sin\delta = (4.4 +2.7-1.8 +- 2.9) x 10^-3 and \delta = 22 +11-12 +9-11 degrees.