Guy Wilkinson

Abstract:

We measure the absolute branching fractions of Ds semileptonic decays where the hadron in the final state is one of φ, η, η′, KS0, K 0, and f0, using 2.8×105 e+e-→DsDs decays collected in the CLEO-c detector at a center-of-mass energy close to 4170 MeV. We obtain B(Ds+→e+νe)=(2.29±0.37±0.11)%, B(Ds+→ηe+νe)= (2.48±0.29±0.13)%, B(Ds+→η′e+νe)=(0.91±0. 33±0.05)%, where the first uncertainties are statistical and the second are systematic. We also obtain B(Ds+→K0e+νe)=(0.37±0.10±0. 02)%, and B(Ds+→K0e+νe)=(0.18±0.07±0.01)%, which are the first measurements of Cabibbo suppressed exclusive Ds semileptonic decays, and, B(Ds+→f0e+νe)×B(f0→π+π-)=(0.13±0.04±0.01) %. This is the first absolute product branching fraction determination for a semileptonic decay including a scalar meson in the final state. © 2009 The American Physical Society.

Abstract:

Using a sample of 2.59×107 ψ(2S) decays collected by the CLEO-c detector, we present results of a search for the decay chain ψ(2S)→π0hc, hc→n(π+π-)π0, n=1, 2, 3. We observe no significant signals for n=1 and n=3 and set upper limits for the corresponding decay rates. First evidence for the decay hc→π+π-π+π-π0 is presented, and a product branching fraction of B(ψ(2S)→hcπ0) ×B(hc→2(π+π-)π0)=1.88-0.45-0.30+0.48+0.47×10-5 is measured. This result implies that hc→hadrons and hc→γηc have comparable rates, in agreement with expectations. © 2009 The American Physical Society.

Abstract:

Using data collected near the Ds* ± Ds Ds peak production energy E cm 4170 MeV by the CLEO-c detector, we search for Ds+ exclusive hadronic decays involving. We find B Ds+ n+ w 0.21 ± 0.09 ± %, B Ds+ n+ 2.78 ± 0.65 ± 0.25 %, Ds+ n+ n+ n- 1.58 ± 0.09%. Ds+ n+ 0.85± 0.54 ± 0.06%. K+. n+ n- 0.54%, and The upper limits are at 90% confidence level.

Abstract:

The first measurements of the coherence factors (RKππ0 and RK3π) and the average strong-phase differences (δDKππ0 and δDK3π) for D0→K-π+π0 and D0→K-π+π+π- are presented. These parameters can be used to improve the determination of the unitarity triangle angle γ in B-→DK- decays, where D is a D0 or D̄0 meson decaying to the same final state. The measurements are made using quantum-correlated, fully reconstructed D0D̄0 pairs produced in e+e- collisions at the ψ(3770) resonance. The measured values are: RKππ0=0.84±0.07, δDKππ0=(227-17+14)°, RK3π=0.33-0.23+0.20, and δDK3π=(114-23+26)°. These results indicate significant coherence in the decay D0→K-π+π0, whereas lower coherence is observed in the decay D0→K-π+π+π-. The analysis also results in a small improvement in the knowledge of other D-meson parameters, in particular, the strong-phase difference for D0→K-π+, δDKπ, and the mixing parameter y. © 2009 The American Physical Society.