G. P. Chen

First measurement of Γ(D* +) and precision measurement of m D*+-m D0

We present the first measurement of the D*+ width using 9/fb of e+ e- data collected near the Upsilon(4S) resonance by the CLEO II.V detector. Our method uses advanced tracking techniques and a reconstruction method that takes advantage of the small vertical size of the CESR beam spot to measure the energy release distribution from the D*+ -> D0 pi+ decay. We find Gamma(D*+) = 96 +- 4 (Statistical) +- 22 (Systematic) keV. We also measure the energy release in the decay and compute Delta m = m(D*+) - m(D0) = 145.412 +- 0.002 (Statistical) +- 0.012 (Systematic) MeV/c^2

Branching fractions of τ Leptons to three charged Hadrons

From electron-positron collision data collected with the CLEO detector operating at Cornell Electron Storage Ring near sqrt[s]=10.6 GeV, improved measurements of the branching fractions for tau decays into three explicitly identified hadrons and a neutrino are presented as B(tau(-)-->pi(-)pi(+)pi(-)nu(tau))=(9.13+/-0.05+/-0.46)%, B(tau(-)-->K-pi(+)pi(-)nu(tau))=(3.84+/-0.14+/-0.38) x 10(-3), B(tau(-)-->K-K+pi(-)nu(tau))=(1.55+/-0.06+/-0.09) x 10(-3), and B(tau(-)-->K-K+K-nu(tau))<3.7 x 10(-5) at 90% C.L., where the uncertainties are statistical and systematic, respectively.

Measurement of exclusive B decays to final states containing a charmed baryon

Using data collected by the CLEO detector in the Upsilon(4S) region, we report new measurements of the exclusive decays of B mesons into final states of the type Lambda_c^+ p-bar n(pi), where n=0,1,2,3. We find signals in modes with one, two and three pions and an upper limit for the two body decay Lambda_c^+ pbar. We also make the first measurements of exclusive decays of B mesons to Sigma_c p-bar n(pi), where n=0,1,2. We find signals in modes with one and two pions and an upper limit for the two body decay Sigma_c p-bar. Measurements of these modes shed light on the mechanisms involved in B decays to baryons.

Search for neutrinoless τ decays involving the KS 0 meson

We have searched for lepton flavor violating decays of the tau lepton with one or two KS0 mesons in the final state. The data used in the search were collected with the CLEO II and II.V detectors at the Cornell Electron Storage Ring (CESR) and correspond to an integrated luminosity of 13.9 fb^-1 at the Upsilon(4S) resonance. No evidence for signals were found, therefore we have set 90% confidence level (C.L.) upper limits on the branching fractions B(tau -> e KS0) mu KS0) e 2KS0) mu 2KS0) < 3.4e-6. These represent significantly improved upper limits on the two-body decays and first upper limits on the three-body decays.

Search for baryons in the radiative penguin decay b→sγ

We have searched for the baryon-containing radiative penguin decays B^- -> \Lambda p-bar \gamma and B^- -> \Sigma^0 p-bar \gamma, using a sample of 9.7 million BBbar events collected at the \Upsilon(4S) with the CLEO detector. We find no evidence for either, and set 90% confidence level upper limits for photons with B rest frame energy greater than 2.0 GeV of [Br(B^- -> \Lambda p-bar \gamma) + 0.3 Br(B^- -> \Sigma^0 p-bar \gamma)] \Sigma^0 p-bar \gamma) + 0.4 Br(B^- -> \Lambda p-bar \gamma)] < 6.4 x 10^-6. From the latter, we estimate (for photons with B rest frame energy greater than 2.0 GeV) Br(B -> X_s \gamma, X_s containing baryons) s \gamma that are less than half the combined statistical and systematic errors quoted on these quantities.

Measurement of the charge asymmetry in B→K*: (892) ±π∓

We report on a search for a CP-violating asymmetry in the charmless hadronic decay B -> K*(892)+- pi-+, using 9.12 fb^-1 of integrated luminosity produced at \sqrt{s}=10.58 GeV and collected with the CLEO detector. We find A_{CP}(B -> K*(892)+- pi-+) = 0.26+0.33-0.34(stat.)+0.10-0.08(syst.), giving an allowed interval of [-0.31,0.78] at the 90% confidence level.

Measurement of the decay rate of Ξc 0→pK -K-π+ relative to Ξc 0→Ξ-π+

Using the CLEO IIIdetector at CESR, we have measured the branching ratio of the decay [Formula Presented] relative to [Formula Presented] We find [Formula Presented] In the resonant substructure of this mode, we find evidence for [Formula Presented] decays to [Formula Presented] and measure [Formula Presented] and [Formula Presented] for the [Formula Presented] decays.

Measurement of the Ξ c + lifetime

The Xi^+_c lifetime is measured using 9.0 fb^-1 of e+e- annihilation data collected on and just below the Upsilon(4S) resonance with the CLEO II.V detector at CESR. This is the first measurement of the Xi^+_c lifetime from a collider experiment. Using an unbinned maximum likelihood fit, the Xi^+_c lifetime is measured to be 503 +/- 47 (stat.) +/- 18 (syst.) fs. The precision of this measurement is comparable to previous measurements carried out by fixed target experiments with different sources of systematic uncertainties.

First observation of B̄ 0→ D* 0π +π +π -π -decays

We report on the observation of B0bar -> D*0 pi+ pi+ pi- pi- decays. The branching ratio is (0.30 +/- 0.07 +/- 0.06)%. Interest in this particular mode was sparked by Ligeti, Luke and Wise who propose it as a way to check the validity of factorization tests in B0bar -> D*+ pi+ pi- pi- pi0 decays.

Cabibbo-suppressed decays of D+ → π+π 0, K+K̄0,K+π0

Using a 13.7 fb-1 data sample collected with the CLEO II and II.V detectors, we report new branching fraction measurements for two Cabibbo-suppressed decay modes of the D+ meson: BR(D+ -> pi+ pi0) = (1.31 +/- 0.17 +/- 0.09 +/- 0.09) x 10^(-3)and BR(D+ -> K+ K0bar) = (5.24 +/- 0.43 +/- 0.20 +/- 0.34) x 10^(-3) which are significant improvements over past measurements. The errors reflect statistical and systematical uncertainties as well as the uncertainty in the absolute D+ branching fraction scale. We also set the first 90% confidence level upper limit on the branching fraction of the doubly Cabibbo-suppressed decay mode BR(D+ -> K+ pi0) < 4.2 x 10^(-4).K. Arms, E. Eckhart, K. K. Gan, C. Gwon, K. Honscheid, R. Kass, H. Severini, P. Skubic, S.A. Dytman, J.A. Mueller, S. Nam, V. Savinov, J. W. Hinson, G. S. Huang, J. Lee, D. H. Miller, V. Pavlunin, B. Sanghi, E. I. Shibata, I. P. J. Shipsey, D. Cronin-Hennessy, C. S. Park, W. Park, J. B. Thayer, E. H. Thorndike, T. E. Coan, Y. S. Gao, F. Liu, R. Stroynowski, M. Artuso, C. Boulahouache, S. Blusk, E. Dambasuren, O. Dorjkhaidav, R. Mountain, H. Muramatsu, R. Nandakumar, T. Skwarnicki, S. Stone, J.C. Wang, A. H. Mahmood, S. E. Csorna, I. Danko, G. Bonvicini, D. Cinabro, M. Dubrovin, A. Bornheim, E. Lipeles, S. P. Pappas, A. Shapiro, W. M. Sun, A. J. Weinstein, R. A. Briere, G. P. Chen, T. Ferguson, G. Tatishvili, H. Vogel, M. E. Watkins, N. E. Adam, J. P. Alexander, K. Berkelman, V. Boisvert, D. G. Cassel, J. E. Duboscq, K. M. Ecklund, R. Ehrlich, R. S. Galik, L. Gibbons, B. Gittelman, S. W. Gray, D. L. Hartill, B. K. Heltsley, L. Hsu, C. D. Jones, J. Kandaswamy, D. L. Kreinick, A. Magerkurth, H. Mahlke-Krüger, T. O. Meyer, N. B. Mistry, J. R. Patterson, T. K. Pedlar, D. Peterson, J. Pivarski, S. J. Richichi, D. Riley, A. J. Sadoff, H. Schwarthoff, M. R. Shepherd, J. G. Thayer, D. Urner, T. Wilksen, A. Warburton, M. Weinberger, S. B. Athar, P. Avery, L. Breva-Newell, V. Potlia, H. Stoeck, J. Yelton, B. I. Eisenstein, G. D. Gollin, I. Karliner, N. Lowrey, C. Plager, C. Sedlack, M. Selen, J. J. Thaler, J. Williams, K. W. Edwards, D. Besson, V. V. Frolov, D. T. Gong, Y. Kubota, S. Z. Li, R. Poling, A. Smith, C. J. Stepaniak, J. Urheim, Z. Metreveli, K.K. Seth, A. Tomaradze, P. Zweber, and J. Ernst