Guy Wilkinson

Abstract:

Using data collected on the ψ(3770) resonance and near the Ds*±Ds" peak production energy by the CLEO-c detector, we study the decays of the possible D→PP modes and report measurements of or upper limits on all branching fractions for Cabibbo-favored, singly Cabibbo-suppressed, and doubly Cabibbo-suppressed D→PP decays except modes involving KL0 (and except D0→K+π-). We normalize with respect to the Cabibbo-favored D modes, D0→K -π+, D+→K-π +π+, and Ds+→K+KS0. © 2010 The American Physical Society.

Abstract:

We have measured the inclusive semileptonic branching fractions of D0, D⁺, and Ds+ mesons. For these measurements, we have used the full CLEO-c open-charm data samples, 818pb^-1 at ECM=3.774GeV, giving D0D^̄0 and D⁺D^- events, and 602pb ^-1 at ECM=4.170GeV, giving Ds*±Ds" events. We obtain B(D0→Xe⁺νe)=(6.46±0.09±0.11)%, B(D ⁺→Xe⁺νe)=(16.13±0.10±0.29)%, and B(Ds+→Xe⁺νe)=(6.52±0.39±0.15)%, where the first uncertainties are statistical and the second are systematic. From these and lifetimes obtained elsewhere, we obtain the ratios of semileptonic decay widths Γ(D⁺→Xe⁺νe)/Γ(D0→Xe ⁺νe)=0.985±0.015±0.024 and Γ(Ds+→Xe ⁺νe)/Γ(D0→Xe⁺νe)=0.828±0. 051±0.025. The ratio of D⁺ and D0 is consistent with the isospin symmetry prediction of unity, and the ratio of Ds+ and D0 differs from unity, as expected. © 2010 The American Physical Society.

Abstract:

We report a search for the decay ψ(2S)→γηc(2S) in a sample of 25.9×106 ψ(2S) events collected with the CLEO-c detector. No signals are observed in any of the 11 exclusive ηc(2S) decay modes studied, or in their sum. Product branching fraction upper limits are determined as a function of Γ[ηc(2S)] for the 11 individual modes. © 2010 The American Physical Society.

Abstract:

We report evidence for the ground state of bottomonium, ηb(1S), in the radiative decay Υ(3S)→γηb in e+e- annihilation data taken with the CLEO III detector. Using 6×106 Υ(3S) decays, and assuming Γ(ηb)=10±5MeV/c2, we obtain B(Υ(3S)→γηb)=(7.1±1.8±1.3)×10 -4, where the first error is statistical and the second is systematic. The statistical significance is ∼4σ. The mass is determined to be M(ηb)=9391.8±6.6±2.0MeV/c2, which corresponds to the hyperfine splitting ΔMhf(1S)b=68.5±6.6±2.0MeV/c2. Using 9×106 Υ(2S) decays, we place an upper limit on the corresponding Υ(2S) decay, B(Υ(2S)→γηb)<8. 4×10-4 at 90% confidence level. © 2010 The American Physical Society.