Using the entire CLEO-c c ð3770Þ ! D " D event sample, corresponding to an integrated luminosity of 818 pb À1 and approximately 5:4 Â 10 6 D " D events, we present a study of the decays D 0 ! À e þ e , D 0 ! K À e þ e , D þ ! 0 e þ e , and D þ ! " K 0 e þ e . Via a tagged analysis technique, in which one D is fully reconstructed in a hadronic mode, partial rates for semileptonic decays by the other D are measured in several q 2 bins. We fit these rates using several form factor parametrizations and report the results, including form factor shape parameters and the branching fractions BðD 0 ! À e þ e Þ ¼ ð0:288 AE 0:008 AE 0:003Þ%, BðD 0 ! K À e þ e Þ ¼ ð3:50 AE 0:03 AE 0:04Þ%, BðD þ ! 0 e þ e Þ ¼ ð0:405 AE 0:016 AE 0:009Þ%, and BðD þ ! "K 0 e þ e Þ ¼ ð8:83 AE 0:10 AE 0:20Þ%, where the first uncertainties are statistical and the second are systematic. Taking input from lattice quantum chromodynamics, we also find jV cd j ¼ 0:234 AE 0:007 AE 0:002 AE 0:025 and jV cs j ¼ 0:985 AE 0:009 AE 0:006 AE 0:103, where the third uncertainties are from lattice quantum chromodynamics.

Using 20.7 pb −1 of e + e − annihilation data taken at √ s = 3.671 GeV with the CLEO-c detector, precision measurements of the electromagnetic form factors of the charged pion, charged kaon, and proton have been made for timelike momentum transfer of |Q 2 | = 13.48 GeV 2 by the reaction e + e − → h + h − . The measurements are the first ever with identified pions and kaons of |Q 2 | > 4 GeV 2 , with the results F π (13.48 GeV 2 ) = 0.075 ± 0.008(stat) ± 0.005(syst) and F K (13.48 GeV 2 ) = 0.063±0.004(stat)±0.001(syst). The result for the proton, assumingGeV 2 ) = 0.014 ± 0.002(stat) ± 0.001(syst), which is in agreement with earlier results.

Using data collected with the CLEO detector operating at the CESR e+e- collider at sqrt[s]=3.97-4.26 GeV, we investigate 15 charmonium decay modes of the psi(4040), psi(4160), and Y(4260) resonances. We confirm, at 11 sigma significance, the BABAR Y(4260)-->pi+pi- J/psi discovery, make the first observation of Y(4260)--> pi(0)pi(0) J/psi (5.1 sigma), and find the first evidence for Y(4260)-->K+K- J/psi(3.7 sigma). We measure e+e- cross sections at sqrt[s]=4.26 GeV as sigma(pi+pi- J/psi)=58(+12)(-10)+/-4 pb, sigma(pi(0)pi(0) J/psi)=23(+12)(-8)+/-1 pb, and sigma(K+K- J/psi)=9(+9)(-5)+/-1 pb, in which the uncertainties are statistical and systematic, respectively. Upper limits are placed on other decay rates from all three resonances.

We have studied semileptonic B decay to the exclusive charmless states π, ρ/ω, η and η using the full 15.5 fb −1 CLEO Υ(4S) sample, with measurements performed in subregions of phase space to minimize dependence on a priori knowledge of the form factors involved. We find total branching fractions B(B 0 → π − + ν) = (1.37 ± 0.15 stat ± 0.11 sys ) × 10 −4 and B(B 0 → ρ − + ν) = (2.93 ± 0.37 stat ± 0.37 sys ) × 10 −4 . We find evidence for B + → η + ν, with B(B + → η + ν) = (2.66 ± ±0.80 stat ± 0.56 sys ) × 10 −4 and 1.20 × 10 −4 < B(B + → η + ν) < 4.46 × 10 −4 (90% CL). We also limit B(B + → η + ν) < 1.01 × 10 −4 (90% CL). By combining our B → π ν information with unquenched lattice calculations, we find |V ub | = (3.6 ± 0.4 stat ± 0.2 sys +0.6 −0.4thy ) × 10 −3 .2

Using the CLEO-c detector at the Cornell Electron Storage Ring, we have measured inclusive and exclusive cross sections for the production of D + , D 0 and D + s mesons in e + e − annihilations at thirteen center-of-mass energies between 3.97 and 4.26 GeV. Exclusive cross sections are presented for final states consisting of two charm mesons

We report the first determination of the relative strong-phase difference betweenIn addition, we present updated measurements of the relative strong-phase difference betweenBoth measurements exploit the quantum coherence between a pair of D 0 and D 0 mesons produced from ψ(3770) decays.The strong-phase differences measured are important for determining the Cabibbo-Kobayashi-, in a manner independent of the model assumed to describe the D 0 → K 0 S h + h − decay. Using our results, the uncertainty in γ/φ 3 due to the error on the strong-phase difference is expected to be between 1.7 • and 3.9 • for an analysis usingand between 3.2 • and 3.9 • for an analysis based onA measurement is also presented of the CP -odd fraction, F − , of the decay D 0 → K 0 S K + K − in the region of the φ → K + K − resonance. We find that in a region within 0.01 GeV 2 /c 4 of the nominal φ mass squared F − > 0.91 at the 90% confidence level.

We measure the branching ratio of the purely leptonic decay of the D + meson with unprecedented precision as B(D + → µ + ν) = (3.82 ± 0.32 ± 0.09) × 10 −4 , using 818 pb −1 of data taken on the ψ(3770) resonance with the CLEO-c detector at the CESR collider. We use this determination to derive a value for the pseudoscalar decay constant f D + , combining with measurements of the D + lifetime and assuming |V cd | = |V us |. We find f D + = (205.8 ± 8.5 ± 2.5) MeV. The decay rate asymmetry.08 ± 0.08, consistent with no CP violation. We also set 90% confidence level upper limits on B(D + → τ + ν) < 1.2 × 10 −3 and B(D + → e + ν) < 8.8 × 10 −6 .

Using 13.3 fb −1 of e + e − collision data taken in the Υ(1S −4S) region with the CLEO III detector at the CESR collider, a search has been made for the new resonance Y (4260) recently reported by the BaBar Collaboration. The production of Y (4260) in initial state radiation (ISR), and its decay into π + π − J/ψ, are confirmed. A good quality fit to our data is obtained with a single resonance. We determine M (Y (4260)) = (4284 +17 −16 (stat) ± 4(syst)) MeV/c 2 , Γ(Y (4260)) = (73 +39 −25 (stat) ± 5(syst)) MeV/c 2 , and Γ ee (Y (4260)) × B(Y (4260) → π + π − J/ψ) = (8.9 +3.9 −3.1 (stat) ± 1.8(syst)) eV/c 2 .