C. Bebek, ' K. Berkelman, ' E. Blucher, ' J. Byrd ' D. G. Cassel, ' E. Cheu, ' D. M. CoA'man, ' T. Copie, ' G. Crawford, ' R. DeSalvo, ' J. W. DeWire, ' P. Drell, ' R. Ehrlich, ' R. S. Galik, ' B. Gittelman, t'~ S. W. Gray, '~ A. M. Hailing, 't D. L. Hartill, t'~ B. K. Heltsley, t'~ J. Kandaswamy, ' R. Kowalewski, ' D. L. Kreinick, ' Y. Kubota, ' J. D. Lewis, ' N. B. Mistry, ' J. Mueller, ' R. Namjoshi, ' S. Nandi, ' E. Nordberg, ' C. O' Grady, ' D. Perticone, ' D. Peterson, ' M. Pisharody, ' D. Riley, ' M. Sapper, ' A. Silverman, ' S. Stone, ' H. Worden, ' M. Worris, ' A. J. Sado', P. Avery, D. Besson, L. Garren, J. Yelton, T. Bowcock, K. Kinoshita, F. M. Pipkin, M. Procario, Richard Wilson, J. Wolinski, D. Xiao, A. Jawahery, C. H. Park, R. Poling, R. Fulton, P. Haas, M. Hempstead, T. Jensen, D. R. Johnson, H. Kagan, R. Kass, F. Morrow, J. Whitmore, P. Baringer, R. L. McIlwain, D. H. Miller, R. Ng, E. I. Shibata, M. S. Alam, D. Chen, N. Katayama, I. J. Kim, W. C. Li, X. C. Lou, C. R. Sun, V. Tanikella, D. Bortoletto, ' M. Goldberg, ' R. Holmes, ' N. Horwitz, ' P. Lubrano, ' M. D. Mestayer, ' G. C. Moneti, ' V. Sharma, ' I. P. J. Shipsey, ' T. Skwarnicki, ' S. E. Csorna, '' T. Letson, " I. C. Brock, ' T. Ferguson, ' and H. Vogel ' ' Cornell University, Ithaca, New York 14853 1thaca College, Ithaca, New York 14850 ' University of Florida, Gainesville, Florida 326II Harvard University, Cambridge, Massachusetts 02138 t ~University of Maryland, College Park, Maryland, 20742 University of Minnesota, Minneapolis, Minnesota 55455 Ohio State University, Columbus, Ohio, 43210 Purdue University, West Lafayette, Indiana, 47907 'State University of New York at Albany, Albany, New York I2222 ' Syracuse University, Syracuse, New York 13210 " Vanderbilt University, Nashville, Tennessee 37235 Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (Received 3 October 1988)

P. Baringer, ' R. L. McIlwain, ' D. H. Miller, ' E. I. Shibata, ' S. Behrends, Jan M. Guida, Joan A. Guida, F. Morrow, ~ R. Poling, E. H. Thorndike, P. Tipton, M. S. Alam, N. Katayama, I. J. Kim, W. C. Li, X. C. Lou, C. R. Sun, V. Tanikella, D. Bortoletto, M. Goldberg, R. Holmes, N. Horwitz, A. Jawahery, P. Lubrano, G. C. Moneti, V. Sharma, I. P. J. Shipsey, P. Thoma, S. E. Csorna, T. Letson, M. D. Mestayer, R. S. Panvini, G. B. Word, A. Bean, G. J. Bobbink, I. C. Brock, A. Engler, T. Ferguson, R. W. Kraemer, C. Rippich, H. Vogel, C. Bebek, K. Berkelman, E. Blucher, D. G. Cassel, T. Copie, R. DeSalvo, J. W. DeWire, R. Ehrlich, R. S. Galik, M. G. D. Gilchriese, B. Gittelman, S. W. Gray, A. M. Hailing, D. L. Hartill, B. K. Heltsley, S. Holzner, J. Kandaswamy, R. Kowalewski, D. L. Kreinick, Y. Kubota, N. B. M istry, J. Mueller, R. Namjoshi, E. Nordberg, D. Perticone, D. Peterson, M. Pisharody, K. Read, D. Riley, A. Silverman, S. Stone, A. J. SadoA, P. Avery, D. Besson, L. Garren, T. Bowcock, ' K. Kinoshita, ' F. M. Pipkin, ' M. Procario, ' Richard Wilson, ' J. Wolinski, ' D. Xiao, ' P. Haas, '' M. Hempstead, '' T. Jensen, " H. Kagan, '' and R. Kass~'' ' Purdue University, West lafayette, Indiana 47907 University of Rochester, Rochester, New York l4627 State University of New York at Albany, Albany, New York l2222 Syracuse UniI ersity, Syracuse, New York 13210 Vanderbilt University, Nashville, Tennessee 37235 Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 Cornell University, Ithaca, New York 14853 Ithaca College, Ithaca, New York 14850 t 'University of Florida, Gainesville, Florida 326I I Harvard University, Cambridge, Massachusetts 02138 '' Ohio State University, Columbus, Ohio 43210 (Received 29 July 1987)

We measure the absolute branching fraction for D(0)-->K(-)pi(+) using partial reconstruction of B(0)-->D(*+)Xl(-)nu(l) decays, in which only the charged lepton and the pion from the decay D(*+)-->D(0)pi(+) are used. Based on a data sample of 230 x 10(6) BB pairs collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, we obtain B(D(0)-->K(-)pi(+)) = (4.007+/-0.037+/-0.072)%, where the first uncertainty is statistical and the second is systematic.

A measurement of the cross section for gamma gamma --> p ($) over bar p is performed at two-photon center-of-mass energies between 2.00 and 3.25 GeV. These results are obtained using e(+)e(-) --> e(+)e(-)p ($) over bar p events selected from 1.31 fb(-1) of data taken with the CLEO II detector. The measured cross section is in reasonable agreement with previous measurements and is in excellent agreement with recent calculations based on a diquark model. However, leading order QCD calculations performed using the Brodsky-Lepage formalism are well below the measured cross section.

The electrical properties associated with diamond charged particle- and photo-detectors were studied using charged particle-induced conductivity (CPIC) and photo-induced conductivity (PIC). The collection distance d, the product of the excess carrier mobility μ excess carrier lifetime T and electric field E, was used to characterize the diamonds. X-ray diffraction, Raman spectroscopy, photoluminescence, SEM and TEM were performed on CVD diamond detectors to investigate the limitations of the electrical properties. Correlations were found between the electrical properties and the material characterizations.

Using the CLEO II data sample, with an integrated luminosity of 1.8 fb−1 at and near the Υ(4S) resonance, we have observed a signal for D0→K+π−, which could be due to either D0D¯0 mixing or doubly Cabibbo suppressed decay, or a combination of the two. We find scrB(D0→K+π−)/scrB(D0→K−π+)=0.0077±0 .0025(stat) ±0.0025(syst).Received 2 December 1993DOI:https://doi.org/10.1103/PhysRevLett.72.1406©1994 American Physical Society

Using data collected in the region of the γ(4S) resonance with the CLEO II detector operating at the Cornell Electron Storage Ring, we report on evidence for the production of Σ++c and Σ0c baryons in B decays, with Σc→Λ+cπ. This observation is based on 77±19 Σ++c and 76±21 Σ0c candidates from B decays. We find the product branching fractions B(¯B→ΣcX)B(Λ+c→pK−π+) for Σc=Σ++c, Σ0c, and Σ+c to be (2.1 ± 0.8 ± 0.7) × 10−4, (2.3 ± 0.8 ± 0.7) × 10−4, and less than 4.8 × 10−4 at 90% confidence level, respectively. A study of the Σ++c and Σ0c momentum spectra indicates that B decays to two-body final states with Σc are suppressed.Received 21 December 1993DOI:https://doi.org/10.1103/PhysRevLett.73.1472©1994 American Physical Society

A measurement of the cross section for γγ→pp¯ is performed at two-photon center-of-mass energies between 2.00 and 3.25 GeV. These results are obtained using e+e−→e+e−pp¯ events selected from 1.31 fb−1 of data taken with the CLEO II detector. The measured cross section is in reasonable agreement with previous measurements and is in excellent agreement with recent calculations based on a diquark model. However, leading order QCD calculations performed using the Brodsky-Lepage formalism are well below the measured cross section.Received 1 September 1993DOI:https://doi.org/10.1103/PhysRevD.50.5484©1994 American Physical Society

We have observed the previously unseen decay modes LAMBDApi+pi0, SIGMA0pi+pi0 and SIGMA0pi-pi+pi+ of the charmed baryon LAMBDA(c)+, as well as LAMBDA(c)+ --> SIGMA0pi+ observed previously by ARGUS. The branching ratios for these four decay modes relative to LAMBDA(c)+ --> pK-pi+ are measured to be 0.73 +/- 0.09 +/- 0.16, 0.36 +/- 0.09 +/- 0.10, 0.21 +/- 0.05 +/- 0.05, and 0.21 +/- 0.02 +/- 0.04, respectively. Using the recent CLEO measurement of the branching ratio for LAMBDA(c)+ --> pK-pi+, these modes account for 6% of LAMBDA(c)+ decays.

Using data from the CLEO II detector at CESR, we measure the tau-lepton mass by exploiting the unique kinematics of events in which both tau's decay hadronically. The result is m(tau) = 1777.8+/-0.7+/-1.7 MeV/c2. By comparing our result with other measurements near tau-pair threshold, we extract an upper limit on the tau-neutrino mass of 75 MeV/c2 at 95% confidence level.

The decay ${\mathrm{\ensuremath{\tau}}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$${\mathrm{\ensuremath{\pi}}}^{+}$${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$2${\mathrm{\ensuremath{\pi}}}^{0}$${\ensuremath{\nu}}_{\mathrm{\ensuremath{\tau}}}$ has been observed in ${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ annihilation using the CLEO II detector at the Cornell Electron Storage Ring. In a data sample collected at \ensuremath{\surd}s \ensuremath{\sim}10.6 GeV, 668\ifmmode\pm\else\textpm\fi{}38 decay candidates have been identified by exclusively reconstructing two ${\mathrm{\ensuremath{\pi}}}^{0}$'s accompanying three charged particles, which are assumed to be pions. Normalizing to the number of \ensuremath{\tau} pairs detected with one charged particle recoiling against three charged particles, this yields a branching ratio of ${\mathit{B}}_{3\mathrm{\ensuremath{\pi}}2\mathrm{\ensuremath{\pi}}}^{0}$=(0.48\ifmmode\pm\else\textpm\fi{}0.04\ifmmode\pm\else\textpm\fi{}0.04)%. A signal of 430\ifmmode\pm\else\textpm\fi{}33 events for the decay ${\mathrm{\ensuremath{\tau}}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\omega}${\mathrm{\ensuremath{\pi}}}^{0}$${\ensuremath{\nu}}_{\mathrm{\ensuremath{\tau}}}$ has also been observed, corresponding to a branching ratio of ${\mathit{B}}_{\mathrm{\ensuremath{\pi}}\mathrm{\ensuremath{\omega}}\mathrm{\ensuremath{\pi}}}^{0}$=(0.39\ifmmode\pm\else\textpm\fi{}0.04\ifmmode\pm\else\textpm\fi{}0.04)%.

We present a measurement of the lepton decay asymmetry A(fb) in the reaction BBAR --> D*l-v(l)BAR using data collected with the CLEO II detector at the Cornell Electron Storage Ring (CESR). The value of A(fb) confirms that the chirality of the weak interaction is predominantly left-handed in b --> c transitions as expected in the standard model, if it is assumed that the lepton current is also left-handed. Using A(fb) and the previously determined branching ratio, q2 distribution, and D* polarization, we obtain the first measurement of the form-factor ratios that are used to describe this semileptonic decay.

We have observed the decays B0 --> K*(892)0gamma and B- --> K*(892)-gamma, which are evidence for the quark-level process b --> sgamma. The average branching fraction is (4.5 +/- 1.5 +/- 0.9) x 10(-5). This value is consistent with standard model predictions from electromagnetic penguin diagrams.