Guy Wilkinson

Abstract:

Using a sample of 2.59×107 ψ(2S) decays collected by the CLEO-c detector, we present results of a study of χcJ (J=0, 1, 2) decays into baryon-antibaryon final states. We present the world's most precise measurements of the χcJ→pp̄ and χcJ→ΛΛ̄ branching fractions, and the first measurements of χc0 decays to other hyperons. These results illuminate the decay mechanism of the χc states. © 2008 The American Physical Society.

Abstract:

We exploit the quantum coherence between pair-produced D0 and D̄0 in ψ(3770) decays to study charm mixing, which is characterized by the parameters x and y, and to make a first determination of the relative strong phase δ between doubly Cabibbo-suppressed D0→K+π- and Cabibbo-favored D̄0→K+π-. We analyze a sample of 1.0×106 D0D̄0 pairs from 281pb-1 of e+e- collision data collected with the CLEO-c detector at Ecm=3.77GeV. By combining CLEO-c measurements with branching fraction input and time-integrated measurements of RM≡(x2+y2)/2 and RWS≡Γ(D0→K+π-)/Γ(D̄0→K+π-) from other experiments, we find cosδ=1.03-0.17+0.31±0.06, where the uncertainties are statistical and systematic, respectively. In addition, by further including external measurements of charm mixing parameters, we obtain an alternate measurement of cosδ=1.10±0.35±0.07, as well as xsinδ=(4.4-1.8+2.7±2.9)×10-3 and δ=(22-12-11+11+9) °. © 2008 The American Physical Society.

Abstract:

We report determination of branching fractions for the decays ψ(2S)→h+J/ψ, where h=any, π+π-, π0π0, η, π0, and γγ through χc0,1,2. These measurements use 27M ψ(2S) decays produced in e+e- collision data collected with the CLEO detector. The resulting branching fractions and ratios thereof improve upon previously achieved precision in all cases, and in combination with other measurements permit determination of B(χcJ→γJ/ψ) and B(ψ(2S)→light hadrons). © 2008 The American Physical Society.

Abstract:

We exploit the quantum coherence between pair-produced D0 and D̄0 in ψ(3770) decays to study charm mixing, which is characterized by the parameters x and y, and to make a first determination of the relative strong phase δ between D0→K+π- and D̄0→K+π-. Using 281pb-1 of e+e- collision data collected with the CLEO-c detector at Ecm=3.77GeV, as well as branching fraction input and time-integrated measurements of RM(x2+y2)/2 and RWSΓ(D0→K+π-)/Γ(D̄0→K+π-) from other experiments, we find cosδ=1.03-0.17+0.31±0.06, where the uncertainties are statistical and systematic, respectively. By further including other mixing parameter measurements, we obtain an alternate measurement of cosδ=1.10±0.35±0.07, as well as xsinδ=(4.4-1.8+2. 7±2.9)×10-3 and δ=(22-12-11+11+9)°. © 2008 The American Physical Society.

Abstract:

Using 281pb-1 of data collected with the CLEO-c detector, we present new measurements of Cabibbo-suppressed decays of D0 and D+ mesons to η and η′ final states. We make first observations of D0→η′ π0, ηη, ηη′, and ηπ+π-, and find evidence for D+→ηπ+π0, D+→η′π+π0, and D0→η′π+π-. We also report on improved measurements of D0→ηπ0, D+→ηπ+, and D+→η′π+. Using the measured two-body Cabibbo-suppressed decays, we extract amplitudes for specific flavor topologies and compare them to those from Cabibbo-favored decays. © 2008 The American Physical Society.