Measurement of the Strong Phase in D0 -> K+pi- Using Quantum Correlations

TL;DR

This study uses quantum correlations in psi(3770) decays to measure the strong phase difference in D0 decays, providing initial estimates crucial for understanding charm mixing and CP violation.

Contribution

It presents the first measurement of the strong phase etween D0 and D0bar decays to K+pi- using quantum coherence, with preliminary results from CLEO-c data.

Findings

os\u03b4 = 1.03 b1 0.19 b1 0.08 (statistical and systematic)

os\u03b4 = 0.93 b1 0.32 b1 0.04 (including external measurements)

First measurement of the strong phase etween D0 and D0bar decays.

Abstract

We exploit the quantum coherence between pair-produced D0 and D0bar in psi(3770) decays to study charm mixing and to make a first measurement 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 from other experiments, we make a preliminary determination of \cos\delta = 1.03 +- 0.19 +- 0.08, where the uncertainties are statistical and systematic, respectively. By further including other external mixing parameter measurements, we obtain an alternate measurement of \cos\delta = 0.93 +- 0.32 +- 0.04, where the systematic uncertainty from assuming x\sin\delta=0 has not been included.