We analyze a sample of 3 million quantum-correlated D0 D0bar pairs from 818 pb^-1 of e+e- collision data collected with the CLEO-c detector at E_cm = 3.77 GeV, to give an updated measurement of cosdelta and a first determination of sindelta, where de
lta is the relative strong phase between doubly Cabibbo-suppressed D0 --> K+pi- and Cabibbo-favored D0bar --> K+pi- decay amplitudes. With no inputs from other experiments, we find cosdelta = 0.81 +0.22+0.07 -0.18-0.05, sindelta = -0.01 +- 0.41 +- 0.04, and |delta| = 10 +28+13 -53-0 degrees. By including external measurements of mixing parameters, we find alternative values of cosdelta = 1.15 +0.19+0.00 -0.17-0.08, sindelta = 0.56 +0.32+0.21 -0.31-0.20, and delta = (18 +11-17) degrees. Our results can be used to improve the world average uncertainty on the mixing parameter y by approximately 10%.
Using e^+e^- collision data corresponding to 5.88M Y(3S) [25.9M psi(2S)] decays and acquired by the CLEO III [CLEO-c] detectors operating at CESR, we study the single-pion transitions from Y(3S) [psi(2S)] to the respective spin-singlet states h_{b[c]
}. Utilizing only the momentum of suitably selected transition-pi^0 candidates, we obtain the upper limit B(Y(3S) -> pi^0 h_b) < 1.2times 10^{-3} at 90% confidence level, and measure B(psi(2S) -> pi^0 h_c) = (9.0+-1.5+-1.3)times 10^{-4}. Signal sensitivities are enhanced by excluding very asymmetric pi^0 -> gamma gamma candidates.
