Guy Wilkinson

Abstract:

We report the first determination of the relative strong-phase difference between D0→KS,L0K+K- and D⊃̄0→KS, L0K+K-. In addition, we present updated measurements of the relative strong-phase difference between D0→KS, L0π+π- and D⊃̄0→KS,L0π +π-. Both measurements exploit the quantum coherence between a pair of D0 and D⊃̄0 mesons produced from ψ(3770) decays. The strong-phase differences measured are important for determining the Cabibbo-Kobayashi-Maskawa angle γ/Φ3 in B -→K-D⊃0 decays, where D⊃0 is a D0 or D⊃̄0 meson decaying to KS0h+h- (h=π, K), in a manner independent of the model assumed to describe the D0→KS0h +h- decay. Using our results, the uncertainty in γ/Φ3 due to the error on the strong-phase difference is expected to be between 1.7° and 3.9° for an analysis using B -→K-D⊃0, D⊃0→KS0π+π - decays, and between 3.2° and 3.9° for an analysis based on B-→K-D⊃0, D⊃0→KS0K+K - decays. A measurement is also presented of the CP-odd fraction, F-, of the decay D0→KS0K+K- in the region of the Φ→K+K- resonance. We find that in a region within 0.01GeV2/c4 of the nominal Φ mass squared F->0.91 at the 90% confidence level. © 2010 The American Physical Society.

Abstract:

We have searched for flavor-changing neutral current decays and lepton-number-violating decays of D+ and Ds+ mesons to final states of the form h±e e+, where h is either π or K. We use the complete samples of CLEO-c open-charm data, corresponding to integrated luminosities of 818pb-1 at the center-of-mass energy E CM=3.774GeV containing 2.4×106 D+D- pairs and 602pb-1 at ECM=4.170GeV containing 0.6×106 Ds*±Ds pairs. No signal is observed in any channel, and we obtain 90% confidence level upper limits on branching fractions B(D +→π+e+e-)<5. 9×10-6, B(D+→π-e +e+)<1.1×10-6, B(D+→ K+e+e-)<3.0×10-6, B(D +→K-e+e+)<3.5×10 -6, B(Ds+→π+e+e-)<2. 2×10-5, B(Ds+→π-e+e +)<1.8×10-5, B(Ds+→K+e +e-)<5.2×10-5, and B(Ds+→K -e+e+)<1.7×10-5. © 2010 The American Physical Society.