Guy Wilkinson

Abstract:

A search for J/ψ radiative decay to weakly interacting neutral final states was performed using the CLEO-c detector at the Cornell Electron Storage Ring. J/ψ events were selected by observing the hadronic decay ψ(2S)→π+π-J/ψ. A total of 3.7×106 J/ψ events were used to study the decay J/ψ→γ+X, where X is a narrow state that is invisible to the detector. No significant signal was observed, and upper limits on the branching fraction were set for masses mX up to 960MeV/c2. The upper limit corresponding to mX=0 is 4.3×10-6 at the 90% confidence level. © 2010 The American Physical Society.

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 D0D̄0 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.