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22 results on '"H. B. Wald"'

1. Electroweak Effects ine+e−→τ+τ−at 29 GeV

Author

R. Messner, J. H. Moromisato, M. Piccolo, R. Prepost, R. E. Leedy, R. B. Hurst, E. Fernandez, T. L. Lavine, F.J. Ronga, D. M. Ritson, G. B. Chadwick, N. Qi, J. P. Venuti, Tiziano Camporesi, M. C. Delfino, O. A. Meyer, R. W. Zdarko, J. R. Johnson, Andrea Carlo Marini, Hoyun Lee, D. E. Wiser, J. R. Smith, M. W. Gettner, H. T. Blume, E. von Goeler, W. W. Ash, R. W. Coombes, G. P. Goderre, H. S. Kaye, R. de Sangro, H. B. Wald, S. H. Clearwater, L. J. Moss, Roy Weinstein, T. Maruyama, L. J. Rosenberg, B. K. Heltsley, I. M. Peruzzi, H. R. Band, H. L. Lynch, D. E. Groom, J. C. Sleeman, W. T. Ford, F. Muller, H. N. Nelson, Kwong Lau, Alexander Lincoln Read, and W. D. Shambroom

Subjects
Physics, Particle physics, Electroweak interaction, General Physics and Astronomy
Published
1985

2. Observation of charge asymmetry in hadron jets frome+e−annihilation at√s =29GeV

Author

M. W. Gettner, H. N. Nelson, L. J. Rosenberg, Piero Giorgio Verdini, D. E. Groom, J. C. Sleeman, G. P. Goderre, W. T. Ford, J. H. Moromisato, W. D. Shambroom, E. von Goeler, M. Piccolo, H. R. Band, F.J. Ronga, R. B. Hurst, M. C. Delfino, F. Muller, G. B. Chadwick, N. Qi, J. P. Venuti, J. R. Johnson, R. Prepost, I. M. Peruzzi, W. W. Ash, L. J. Moss, J. Pyrlik, Kwong Lau, R. de Sangro, T. Maruyama, Roy Weinstein, T. L. Lavine, J. R. Smith, Tiziano Camporesi, R. W. Zdarko, R. Messner, R. E. Leedy, H. B. Wald, Alexander Lincoln Read, D. M. Ritson, and D. E. Wiser

Subjects
Physics, Particle physics, Annihilation, media_common.quotation_subject, Hadron, General Physics and Astronomy, Charge (physics), Asymmetry, media_common
Published
1987

3. Precision measurement of the total cross section fore+e−→hadrons at a center-of-mass energy of 29 GeV

Author

E. Fernandez, T. L. Lavine, Alexander Lincoln Read, R. B. Hurst, M. W. Gettner, G. B. Chadwick, B. Gottschalk, J. G. Smith, O. A. Meyer, Tiziano Camporesi, J. P. Venuti, D. E. Wiser, L. J. Moss, R. Prepost, W. W. Ash, Frederic Jean Ronga, Roy Weinstein, H. B. Wald, Hoyun Lee, M. C. Delfino, D. M. Ritson, R. W. Zdarko, H. N. Nelson, J. H. Moromisato, R. Messner, K. Rich, E. von Goeler, Andrea Carlo Marini, D. E. Groom, J. C. Sleeman, W. T. Ford, S. H. Clearwater, R. E. Leedy, L. J. Rosenberg, W. D. Shambroom, K. H. Lau, Brian Heltsley, E. C. Loh, N. Qi, J.R. Johnson, T. Maruyama, M. Piccolo, H. L. Lynch, H. R. Band, S. J. Michalowski, R. W. Coombes, F. Muller, R. de Sangro, H. T. Blume, I. M. Peruzzi, G. P. Goderre, and H. S. Kaye

Subjects
Nuclear physics, Quantum chromodynamics, Physics, Coupling constant, Particle physics, Muon, Annihilation, Pair production, Electron–positron annihilation, Hadron, High Energy Physics::Experiment, Elementary particle
Abstract

We report a high-precision measurement of the ratio R of the total cross section for e/sup +/e/sup -/..-->..hadrons to that for e/sup +/e/sup -/..--> mu../sup +/..mu../sup -/, at a center-of-mass energy of 29.0 GeV using the MAC detector. The result is R = 3.96 +- 0.09. This value of R is used to determine a value of the strong coupling constant ..cap alpha../sub s/ of 0.23 +- 0.06, nearly independent of fragmentation models. Two different analysis methods having quite different event-selection criteria have been used and the results are in agreement. Particular attention has been given to the study of systematic errors. New higher-order QED calculations are used for the luminosity determination and the acceptance for hadrons.

Published
1985

4. search for single photons from radiative neutrino or supersymmetric-particle production

Author

J. P. Venuti, Roy Weinstein, Tiziano Camporesi, M. W. Gettner, Piero Giorgio Verdini, J. Pyrlik, L. J. Rosenberg, Alexander Lincoln Read, E. von Goeler, T. L. Lavine, J. H. Moromisato, D. E. Groom, R. W. Zdarko, J. C. Sleeman, W. T. Ford, G. P. Goderre, M. Piccolo, R. B. Hurst, M. C. Delfino, F. Muller, D. M. Ritson, R. Messner, H. B. Wald, W. D. Shambroom, G. B. Chadwick, H. N. Nelson, Kwong Lau, N. Qi, D. E. Wiser, J. R. Johnson, R. E. Leedy, R. Prepost, I. M. Peruzzi, W. W. Ash, L. J. Moss, T. Maruyama, J. R. Smith, and H. R. Band

Subjects
Physics, Nuclear physics, Massless particle, Particle physics, Annihilation, Astrophysics::High Energy Astrophysical Phenomena, Electron–positron annihilation, High Energy Physics::Experiment, Invariant mass, Elementary particle, Neutrino, Lepton, Luminosity
Abstract

Final results are presented from a search for single-photons produced in association with neutrinos or other weakly interacting neutral particles in e/sup +/e/sup -/ annihilations at ..sqrt..s = 29 GeV. The search was performed with the MAC detector at PEP in a total integrated luminosity of 177 pb/sup -1/. The search limits the number of light-neutrino families to N/sub nu/ 50 GeV/c/sup 2/ if m/sub e tilde L/ = m/sub e tilde R/ and m/sub ..gamma.. tilde/ = 0. The mass of the wino is limited to m/sub W tilde/ > 51 GeV/c/sup 2/ if m/sub nu tilde/ = 0. These limits are at the 90% confidence level.

Published
1986

5. Measurement of energy-energy correlations ine+e−→hadrons at√s=29 GeV

Author

B. K. Heltsley, G. B. Chadwick, H. R. Band, Peruzzi I I, R. Prepost, H. Y. Lee, de Sangro R, D. E. Wiser, F.J. Ronga, Kwong Lau, Andrea Carlo Marini, F. Muller, von Goeler E, G. P. Goderre, H. S. Kaye, D. M. Ritson, H. T. Blume, O. A. Meyer, J. R. Smith, R. W. Coombes, M. W. Gettner, R. B. Hurst, W. D. Shambroom, H. N. Nelson, H. B. Wald, T. Maruyama, Alexander Lincoln Read, W. W. Ash, S. H. Clearwater, L. J. Rosenberg, N. Qi, D. E. Groom, J. C. Sleeman, W. T. Ford, Roy Weinstein, E. Fernandez, T. L. Lavine, M. C. Delfino, J. H. Moromisato, M. Piccolo, J. P. Venuti, L. J. Moss, Tiziano Camporesi, H. L. Lynch, R. W. Zdarko, R. Messner, Johnson, and R. E. Leedy

Subjects
Nuclear physics, Quantum chromodynamics, Physics, Particle physics, Annihilation, Electron–positron annihilation, Monte Carlo method, Quark model, Lund string model, High Energy Physics::Experiment, Elementary particle, Gluon
Abstract

The energy-energy correlation cross section for hadrons produced in electron-positron annihilation at a center-of-mass energy of 29 GeV has been measured with the MAC detector at SLAC. The result is corrected for the effects of detector resolution, acceptance, and initial-state radiation. The correlation is measured in two independent ways on the same data sample: the energy weights and angles are obtained either from the energy flow in the finely segmented total absorption calorimeters or from the momenta of charged tracks in the central drift chamber. This procedure helps reduce systematic errors by cross-checking the effects of the detector on the measurement, particularly important because the corrections depend on complex Monte Carlo simulations. The results are compared with the predictions of Monte Carlo models of complete second-order perturbative quantum chromodynamics and fragmentation, with the following conclusions: (1) fitting the asymmetry for large correlation angles gives values for ..cap alpha../sub S/ of 0.120 +- 0.006 in perturbation theory, 0.185 +- 0.013 in the Lund string model, and values which vary from 0.105 to 0.140 ( +- 0.01) in the incoherent jet models, depending on the gluon fragmentation scheme and the algorithm used for momentum conservation; and (2) the string fragmentation model providesmore » a satisfactory description of the measured energy-energy correlation cross section, whereas incoherent jet formation does not.« less

Published
1985

6. Lifetime of Particles ContainingbQuarks

Author

E. Fernandez, W. T. Ford, A. L. Read, J. G. Smith, R. De Sangro, A. Marini, I. Peruzzi, M. Piccolo, F. Ronga, H. T. Blume, H. B. Wald, Roy Weinstein, H. R. Band, M. W. Gettner, G. P. Goderre, B. Gottschalk, R. B. Hurst, O. A. Meyer, J. H. Moromisato, W. D. Shambroom, E. von Goeler, W. W. Ash, G. B. Chadwick, S. H. Clearwater, R. W. Coombes, H. S. Kaye, K. H. Lau, R. E. Leedy, H. L. Lynch, R. L. Messner, S. J. Michalowski, K. Rich, D. M. Ritson, L. J. Rosenberg, D. E. Wiser, R. W. Zdarko, D. E. Groom, Hoyun Lee, E. C. Loh, M. C. Delfino, B. K. Heltsley, J. R. Johnson, T. L. Lavine, T. Maruyama, and R. Prepost

Subjects
Physics, Semileptonic decay, Particle physics, Annihilation, Muon, Meson, High Energy Physics::Phenomenology, Hadron, General Physics and Astronomy, Elementary particle, Nuclear physics, Particle decay, High Energy Physics::Experiment, Nuclear Experiment, Lepton
Abstract

From a sample of hadronic events, produced in e/sup +/e/sup -/ collisions, semileptonic decays of heavy particles have been isolated and used to obtain a measurement for the bottom-quark lifetime of (1.8 +- 0.6(stat.) +- 0.4(syst.)) x 10/sup -12/ sec.

Published
1983

7. Lifetimes of Charmed Particles Produced in a 20-GeVγpExperiment

Author

A. V. Bevan, R. C. Field, James Shank, K.C. Moffeit, J. T. Carroll, F. Ochiai, W. M. Bugg, M. Jobes, T. Sato, J. Ballam, R. N. Diamond, T. Handler, J. S. Chima, G. E. Kalmus, J. Goldberg, T. Maruyama, H. B. Wald, M. MacDermott, G. T. Condo, C. Milstene, Vasken Hagopian, G. P. Gopal, J. J. Murray, R. Erickson, C. A. Woods, A. Napier, B. Franek, A. Suzuki, T. Hayashino, Geoffrey Hall, C. K. Sinclair, S. Yamashita, Aharon Levy, D. H. Brick, L. Berny, C. V. Cautis, W. J. Robertson, W. Cameron, P. Rankin, E. S. Hafen, S. W. O'Neale, Koji Abe, P. W. Lucas, H. J. Hargis, H. H. Bingham, E. Ronat, Shlomo Dado, L.R. Fortney, P. J. Dornan, Edwin R. Hancock, S. Noguchi, R. H. Milburn, K. Tamai, S. Tanaka, A. T. Goshaw, P. Haridas, A. M. Shapiro, H. Yuta, H. Rudnicka, S. Tether, A. Yamaguchi, K. Takahashi, R. A. Gearhart, M. Widgoff, George P Yost, J. Schneps, T. Kitagaki, W. A. Mann, S. Isaacson, W. D. Walker, Y. Yoshimura, R. Merenyi, D. Q. Huang, J. N. Butler, J. E. Brau, P. Lang, H. O. Cohn, M. Rabin, Kazuo Hasegawa, E. L. Hart, S. Wolbers, A. P. T. Palounek, Yuying Wu, R. Sugahara, T. C. Bacon, J. Kent, T. Fieguth, N. Fujiwara, I. A. Pless, A. H. Rogers, G. Yekutieli, D. P. Kelsey, R. I. Hulsizer, C. G. Wilkins, D. C. Colley, R. K. Yamamoto, and J. E. Lannutti

Subjects
Nuclear physics, Physics, Particle decay, Hadron, Monte Carlo method, General Physics and Astronomy, Bubble chamber, Elementary particle, Atomic physics, Laser beams
Abstract

Eleven neutral and nine charged decays of charmed particles have been observed in a sample of 205 000 hadronic interactions in a 1.2-million-picture exposure of the SLAC Hybrid Facility bubble chamber to a 20-GeV/c backward-scattered laser beam. The charged and neutral lifetimes were determined to be ${8.2}_{\ensuremath{-}2.5}^{+4.5}$\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}13}$ and ${6.7}_{\ensuremath{-}2.0}^{+3.5}$\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}13}$ sec, respectively, with a ratio of ${1.2}_{\ensuremath{-}0.5}^{0.9}$.

Published
1982

8. Search for Singly Produced Supersymmetric Electrons ine+e−Interactions

Author

I. M. Peruzzi, S. J. Michalowski, G. P. Goderre, H. S. Kaye, D. M. Ritson, L. J. Rosenberg, H. L. Lynch, S. H. Clearwater, F.J. Ronga, M. W. Gettner, J. H. Moromisato, M. C. Delfino, G. B. Chadwick, M. Piccolo, R. de Sangro, B. K. Heltsley, H. R. Band, E. von Goeler, D. E. Groom, W. T. Ford, R. W. Coombes, K. Rich, H. B. Wald, W. D. Shambroom, R. B. Hurst, Alexander Lincoln Read, E. Fernandez, T. L. Lavine, R. Prepost, H. Y. Lee, R. W. Zdarko, R. Messner, Roy Weinstein, J. P. Venutti, R. E. Leedy, Andrea Carlo Marini, J. R. Smith, D. E. Wiser, T. Maruyama, H. T. Blume, Kwong Lau, O. A. Meyer, J. R. Johnson, W. W. Ash, and E. C. Loh

Subjects
Physics, Particle physics, Angular distribution, Mathematics::Probability, Electron spectra, High Energy Physics::Phenomenology, General Physics and Astronomy, High Energy Physics::Experiment, Production (computer science), Elementary particle, Electron, Lower limit
Abstract

A search for supersymmetric electron production via the reaction ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}^{\ifmmode\pm\else\textpm\fi{}}\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\gamma}}{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{e}}^{\ensuremath{\mp}}$ followed by the decay ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{e}}^{\ensuremath{\mp}}\ensuremath{\rightarrow}{e}^{\ensuremath{\mp}}\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\gamma}}$ has been performed with the MAC detector at the electron-positron storage ring PEP. No candidates were found in a sample corresponding to an integrated luminosity of 36.4 ${\mathrm{pb}}^{\ensuremath{-}1}$. For a massless $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\gamma}}$ this corresponds to a lower limit on the $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{e}$ mass of 22.4 GeV/${\mathit{c}}^{2}$ at the 95% confidence level.

Published
1984

9. Tests of quantum electrodynamics with two-, three-, and four-photon final states frome+e−annihilation at√s =29GeV

Author

H. N. Nelson, Kwong Lau, M. W. Gettner, J. P. Venuti, G. P. Goderre, L. J. Rosenberg, Tiziano Camporesi, H. B. Wald, R. W. Zdarko, J. H. Moromisato, R. Messner, M. Piccolo, F. Muller, R. B. Hurst, H. R. Band, H. T. Blume, R. E. Leedy, W. D. Shambroom, D. M. Ritson, I. M. Peruzzi, J. C. Sleeman, W. T. Ford, G. B. Chadwick, D. E. Wiser, J. R. Smith, E. von Goeler, L. J. Moss, J. Pyrlik, E. Fernandez, And Roy Weinstein, N. Qi, W. W. Ash, and Alexander Lincoln Read

Subjects
Physics, Massless particle, Particle physics, Annihilation, Astrophysics::High Energy Astrophysical Phenomena, Electron–positron annihilation, Quantum electrodynamics, Center (category theory), Propagator, Order (ring theory), Elementary particle, Energy (signal processing)
Abstract

High-precision measurements of electron-positron annihilation into final states of two, three, and four photons are presented. The data were obtained with the MAC detector at the PEP storage ring of the Stanford Linear Accelerator Center, at a center-of-mass energy of 29 GeV. The measured ${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma} differential cross section is used to test the validity of quantum electrodynamics (QED) in this energy range; it agrees well with QED, and the limit on cutoff parameters for the electron propagator is \ensuremath{\Lambda}g66 GeV. The measurement of ${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\gamma} is used to test the QED calculations of order ${\ensuremath{\alpha}}^{3}$ and to search for anomalies that would indicate the existence of new particles; the agreement with QED is excellent and no anomalies are found. Two events from the reaction ${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\gamma} are found, in agreement with the QED prediction.

Published
1987

10. Precision Measurement of Electroweak Effects ine+e−→μ+μ−ats=29GeV

Author

E. Fernandez, T. L. Lavine, G. P. Goderre, Kwong Lau, Tiziano Camporesi, I. M. Peruzzi, J. R. Johnson, J. H. Moromisato, H. N. Nelson, M. Piccolo, R. W. Zdarko, R. Messner, Roy Weinstein, W. W. Ash, F. Muller, R. E. Leedy, H. R. Band, S. H. Clearwater, J. P. Venuti, M. C. Delfino, R. B. Hurst, R. W. Coombes, M. W. Gettner, H. B. Wald, N. Qi, L. J. Rosenberg, E. von Goeler, D. E. Wiser, T. Maruyama, L. J. Moss, Alexander Lincoln Read, I. Lippi, D. E. Groom, J. C. Sleeman, W. T. Ford, J. R. Smith, B. K. Heltsley, D. M. Ritson, W. D. Shambroom, G. B. Chadwick, R. Prepost, and H. T. Blume

Subjects
Physics, Particle physics, Electroweak interaction, General Physics and Astronomy, Micro/Micro
Published
1985

11. Direct Photon Production ine+e−Annihilation

Author

H. T. Blume, H. R. Band, Tiziano Camporesi, G. P. Goderre, H. S. Kaye, Andrea Carlo Marini, Kwong Lau, L. J. Moss, J. P. Venuti, F. Muller, G. B. Chadwick, R. W. Coombes, R. W. Zdarko, R. Messner, H. B. Wald, Johnson, H. Y. Lee, O. A. Meyer, R. Prepost, J. H. Moromisato, R. E. Leedy, de Sangro R, M. Piccolo, B. K. Heltsley, M. C. Delfino, F.J. Ronga, M. W. Gettner, L. J. Rosenberg, R. B. Hurst, H. N. Nelson, E. Fernandez, T. L. Lavine, D. M. Ritson, Peruzzi I I, T. Maruyama, D. E. Groom, J. C. Sleeman, W. T. Ford, W. D. Shambroom, H. L. Lynch, J. R. Smith, W. W. Ash, Roy Weinstein, S. H. Clearwater, D. E. Wiser, N. Qi, Alexander Lincoln Read, and von Goeler E

Subjects
Physics, Quark, Particle physics, Annihilation, Electron–positron annihilation, media_common.quotation_subject, High Energy Physics::Phenomenology, Hadron, Quark model, General Physics and Astronomy, Charge (physics), Elementary particle, Asymmetry, Nuclear physics, High Energy Physics::Experiment, Nuclear Experiment, media_common
Abstract

Direct photon production in hadronic events from e/sup +/e/sup -/ annihilation has been studied at ..sqrt..s = 29 GeV with use of the MAC detector at the PEP storage ring. A charge asymmetry A = (-12.3 +- 3.5)% is observed in the final-state jets. The cross section and the charge asymmetry are in good agreement with the predictions of the fractionally charged quark-parton model. Both the charge asymmetry and total yield have been used to determine values of quark charges. Limits have been established for anomalous sources of direct photons.

Published
1985

12. The MAC detector

Author

J.V. Allaby, R.M. Morse, J.S. Marsh, H. T. Blume, I. M. Peruzzi, F. Muller, R. Messner, S. Morcos, H. L. Lynch, G. B. Chadwick, Roy Weinstein, H. B. Wald, J. P. Venuti, D. E. Wiser, M. C. Delfino, R. E. Leedy, L.A. Baksay, M. W. Gettner, R. Prepost, W.L. Faissler, O. A. Meyer, Frederic Jean Ronga, Andrea Carlo Marini, L. J. Moss, I. Lippi, M. Bosman, Brian Heltsley, S. J. Michalowski, J. Pyrlik, J. H. Moromisato, Alexander Lincoln Read, Y. Goldschmidt-Clermont, H.Y. Lee, E. Fernandez, Tiziano Camporesi, H. N. Nelson, R. W. Coombes, L. J. Rosenberg, T. L. Lavine, R. de Sangro, R. W. Zdarko, J. G. Smith, B. Gottschalk, W. D. Shambroom, J.R. Johnson, G. P. Goderre, H. S. Kaye, D. M. Ritson, K. Rich, M. Piccolo, H. R. Band, E. C. Loh, S.P. Leung, W. W. Ash, D. E. Groom, J. C. Sleeman, W. T. Ford, N. Qi, S. H. Clearwater, R. B. Hurst, Piero Giorgio Verdini, T. Maruyama, E. von Goeler, and K. H. Lau

Subjects
Physics, Nuclear and High Energy Physics, Muon, Luminosity (scattering theory), Physics::Instrumentation and Detectors, business.industry, Detector, Solid angle, Electron, Particle identification, Nuclear physics, Momentum, Data acquisition, Optics, High Energy Physics::Experiment, business, Instrumentation
Abstract

The MAC detector at PEP recorded data for an integrated luminosity of 335 pb −1 between 1980 and 1986. The design of this low-cost MA gnetic C alorimeter was optimized for electron and muon identification, as well as for the measurement of hadronic energy flow. Muon identification is available over 96% of the solid angle, and MAC was the first detector to make large-scale use of gas-sampling calorimetry. Electromagnetic calorimetry in the central section employs alternating layers of lead and proportional wire chambers (PWCs), and hadron and the remaining electromagnetic calorimetry is accomplished with iron plate and PWC layers. A relatively small central drift chamber in an axial magnetic field provides pattern recognition and modest momentum determination. An outer blanket of drift tubes completes the muon identification system. During the latter two years of operation an innovative “soda straw” vertex chamber made more precise lifetime measurements possible. With an evolving trigger system and highly automated data acquisition system, this modest detector has exceeded most of its designers' expectations and has produced a gratifying spectrum of physics results.

Published
1989

13. Measurement ofτLifetime and Branching Ratios

Author

R. B. Hurst, L. J. Moss, F. Muller, J. R. Smith, Kwong Lau, E. von Goeler, M. C. Delfino, S. H. Clearwater, L. J. Rosenberg, Roy Weinstein, H. R. Band, G. P. Goderre, H. S. Kaye, J. P. Venuti, O. A. Meyer, M. W. Gettner, I. M. Peruzzi, D. M. Ritson, D. E. Groom, J. C. Sleeman, G. B. Chadwick, W. T. Ford, Hoyun Lee, E. Fernandez, T. L. Lavine, R. Messner, Frederic Jean Ronga, H. B. Wald, R. W. Coombes, H. L. Lynch, D. E. Wiser, H. N. Nelson, R. de Sangro, J. H. Moromisato, R. E. Leedy, W. W. Ash, Tiziano Camporesi, T. Maruyama, M. Piccolo, R. W. Zdarko, N. Qi, H. T. Blume, Andrea Carlo Marini, B. K. Heltsley, J.R. Johnson, W. D. Shambroom, R. Prepost, and Alexander Lincoln Read

Subjects
Physics, Particle physics, Branching fraction, Electron–positron annihilation, General Physics and Astronomy, Elementary particle
Abstract

Precise results are reported for the $\ensuremath{\tau}$-lepton lifetime and several $\ensuremath{\tau}$ branching ratios obtained with the MAC detector operating at PEP at $\sqrt{s}=29$ GeV. We find ${\ensuremath{\tau}}_{\ensuremath{\tau}}=(3.15\ifmmode\pm\else\textpm\fi{}0.36\ifmmode\pm\else\textpm\fi{}0.4)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}$ sec. Results for the topological branching ratios ${B}_{1}$, ${B}_{3}$, ${B}_{5}$ ($\ensuremath{\tau}$ decaying into 1, 3, 5 charged particles) are ${B}_{3}\ensuremath{\equiv}1\ensuremath{-}{B}_{1}=0.133\ifmmode\pm\else\textpm\fi{}0.003\ifmmode\pm\else\textpm\fi{}0.006$ and ${B}_{5}l0.0017$ at the 95% confidence level. The fraction of all three-prong decays unaccompanied by ${\ensuremath{\pi}}^{0}'\mathrm{s}$ is found to be 0.61\ifmmode\pm\else\textpm\fi{}0.03\ifmmode\pm\else\textpm\fi{}0.05.

Published
1985

14. Search for single electrons from supersymmetric-particle production

Author

Alexander Lincoln Read, L. J. Rosenberg, E. Fernandez, T. L. Lavine, F. Muller, D. E. Groom, J. C. Sleeman, Roy Weinstein, N. Qi, W. T. Ford, H. B. Wald, J. R. Smith, M. W. Gettner, J. Pyrlik, H. R. Band, D. M. Ritson, J. P. Venuti, J. R. Johnson, J. H. Moromisato, M. Piccolo, H. N. Nelson, W. W. Ash, G. P. Goderre, R. Messner, T. Maruyama, R. E. Leedy, I. M. Peruzzi, Tiziano Camporesi, G. B. Chadwick, R. W. Zdarko, M. C. Delfino, R. Prepost, W. D. Shambroom, D. E. Wiser, Piero Giorgio Verdini, E. von Goeler, R. B. Hurst, L. J. Moss, and Kwong Lau

Subjects
Physics, Particle physics, Annihilation, Computer Science::Information Retrieval, Elementary particle, Particle identification, Luminosity, Massless particle, High Energy Physics::Experiment, Neutrino, Computer Science::Data Structures and Algorithms, MathematicsofComputing_DISCRETEMATHEMATICS, Lepton, Bhabha scattering
Abstract

A search for single electrons produced by the decay of singly produced supersymmetric electrons (e-italic-tilde) or W's (W-italic-tilde) within the MAC detector at the SLAC storage ring PEP has been performed in e/sup +/e/sup -/ annihilations at ..sqrt..s = 29 GeV. No evidence of supersymmetric-particle production is observed in a data sample with an integrated luminosity of 206 pb/sup -1/. Limits on possible masses of supersymmetric electrons and photons (gamma-tilde) are presented. The e-italic-tilde mass limit is m/sub e-italic-tilde/>24.5 GeV/c/sup 2/ at the 90% confidence level if m/sub e-italic-tilde//sub >//sub L//sub =/ = m/sub e-tilde//sub =/ and m/sub gamma-tilde/ = 0. If m/sub e-italic-tilde//sub >//sub L//sub =/>>m/sub e-tilde//sub =/, the corresponding limit is m/sub e-italic-tilde//sub >//sub R//sub =/>23.3 GeV/c/sup 2/. Limits on possible masses of supersymmetric W's and neutrino's (nu-tilde) are also presented. The W-italic-tilde mass limit is m/sub W-italic-tilde/>22.0 GeV/c/sup 2/ at the 90% confidence level if m/sub nu-tilde/ = 0.

Published
1987

15. Electroweak effects ine+e−→e+e−at√s=29 GeV

Author

R. Prepost, W. W. Ash, Kwong Lau, F. Muller, J. P. Venuti, J. R. Smith, J. H. Moromisato, M. Piccolo, Tiziano Camporesi, J. Pyrlik, H. R. Band, D. M. Ritson, R. W. Zdarko, Piero Giorgio Verdini, G. B. Chadwick, M. C. Delfino, M. W. Gettner, R. Messner, Johnson, R. B. Hurst, Alexander Lincoln Read, R. E. Leedy, B. K. Heltsley, E. Fernandez, T. Maruyama, T. L. Lavine, W. D. Shambroom, N. Qi, H. T. Blume, L. J. Moss, H. B. Wald, L. J. Rosenberg, Peruzzi I I, D. E. Wiser, H. N. Nelson, von Goeler E, G. P. Goderre, D. E. Groom, J. C. Sleeman, W. T. Ford, and Weinstein aR

Subjects
Physics, Elastic scattering, Nuclear physics, Particle physics, Luminosity (scattering theory), Scattering, High Energy Physics::Phenomenology, Electroweak interaction, High Energy Physics::Experiment, Electron, Particle detector, Storage ring, Bhabha scattering
Abstract

A high-precision measurement of the differential cross section for Bhabha scattering (e/sup +/e/sup -/..-->..e/sup +/e/sup -/) is presented. The measurement was performed with the MAC detector at the PEP storage ring of the Stanford Linear Accelerator Center, at a center-of-mass energy of 29 GeV. Effects due to electroweak interference are observed and agree well with the predictions of the Glashow-Salam-Weinberg model. The agreement between the data and the electroweak prediction rules out substructure of the electron up to mass scales of 1 TeV.

Published
1987

16. Design, construction, prototype tests and performance of a vertex chamber for the MAC detector

Author

H. N. Nelson, D. E. Wiser, D. M. Ritson, G. L. Godfrey, M. Piccolo, M. W. Gettner, I. M. Peruzzi, J. H. Moromisato, G. P. Goderre, G. B. Chadwick, R. B. Hurst, M. Bosman, H. B. Wald, J.R. Johnson, T. Maruyama, L. J. Rosenberg, J. Pyrlik, W. D. Shambroom, R. de Sangro, D. E. Groom, J. C. Sleeman, W. T. Ford, F. Muller, W. W. Ash, Elliott D. Bloom, Alexander Lincoln Read, Roy Weinstein, H. R. Band, R. Prepost, Piero Giorgio Verdini, J. P. Venuti, T. L. Lavine, Kwong Lau, M. C. Delfino, N. Qi, J. R. Smith, E. von Goeler, R. Messner, R. E. Leedy, Tiziano Camporesi, R. W. Zdarko, L. J. Moss, and I. Lippi

Subjects
Physics, Nuclear and High Energy Physics, Argon, business.industry, Detector, chemistry.chemical_element, Tracking (particle physics), law.invention, Pressure measurement, Optics, chemistry, Beamline, law, Electromagnetic shielding, business, Instrumentation, Image resolution, Bhabha scattering
Abstract

The design considerations, construction techniques, prototype tests and performance characteristics of a pressurized drift chamber used in the MAC detector at PEP are described. The chamber consists of 324 aluminized mylar tubes of 6.9 mm diameter with wall thickness of 100 μm. With appropriate shielding it operates successfully at 4.6 cm from the beam line. It was simple to construct and was configured to permit any malfunctioning tubes to be remotely disconnected without affecting operation. The chamber operated without problems for two years in the PEP environment with a gas mixture of 49.5% argon, 49.5% CO 2 , 1% CH 4 , at 4 atm absolute pressure. The mean spatial resolution averaged over all tubes was 45 μm. The time to distance relation for this gas mixture, along with the geometric positioning of individual wires relative to the central tracking chamber, was obtained with data from Bhabha scattering events. We also describe resolution studies performed with a prototype chamber in a SLAC test beam. A wide range of gases, gas pressures, and electronic parameters were explored. These studies proved that resolutions in the 10–50 μm range were possible. Our experience demonstrates that chambers of this type provide high precision tracking and are particularly suited for operation in regions with difficult physical access and/or high ambient radiation levels.

Published
1987

17. Precise measurement of the branching fraction for the decay τ→ντπ

Author

R. W. Zdarko, H. N. Nelson, R. Messner, M. W. Gettner, T. Maruyama, Johnson, R. E. Leedy, H. R. Band, R. B. Hurst, M. C. Delfino, R. Prepost, Peruzzi I I, D. E. Wiser, J. R. Smith, Roy Weinstein, J. P. Venuti, W. W. Ash, F. Muller, Piero Giorgio Verdini, Alexander Lincoln Read, Kwong Lau, D. M. Ritson, G. B. Chadwick, D. E. Groom, J. Pyrlik, J. C. Sleeman, von Goeler E, W. T. Ford, J. H. Moromisato, G. P. Goderre, L. J. Moss, M. Piccolo, H. B. Wald, T. L. Lavine, L. J. Rosenberg, W. D. Shambroom, N. Qi, and Tiziano Camporesi

Subjects
Physics, Nuclear physics, Semileptonic decay, Particle decay, Particle physics, Pion, Meson, Branching fraction, Hadron, Neutrino, Lepton
Abstract

A sample of events from the process e/sup +/e/sup -/..-->..tau/sup +/tau/sup -/ observed with the MAC detector operating at the SLAC storage ring PEP is used for a precise measurement of B/sub ..pi../, the branching fraction for the decay tau..--> nu../sub tau/..pi... The result B/sub ..pi../ = 0.107 +- 0.005 +- 0.008 is obtained from a sample of events with 798 identified pions.

Published
1987

18. Search for Monojet Production ine+e−Annihilation

Author

W. W. Ash, H. R. Band, H. T. Blume, T. Camporesi, G. B. Chadwick, S. H. Clearwater, R. W. Coombes, M. C. Delfino, R. De Sangro, E. Fernandez, W. T. Ford, M. W. Gettner, G. P. Goderre, D. E. Groom, B. K. Heltsley, R. B. Hurst, J. R. Johnson, K. H. Lau, T. L. Lavine, H. Y. Lee, R. E. Leedy, A. Marini, T. Maruyama, R. L. Messner, J. H. Moromisato, L. J. Moss, F. Muller, H. N. Nelson, I. Peruzzi, M. Piccolo, R. Prepost, N. Qi, A. L. Read, D. M. Ritson, L. J. Rosenberg, W. D. Shambroom, J. C. Sleeman, J. G. Smith, J. P. Venuti, E. von Goeler, H. B. Wald, Roy Weinstein, D. E. Wiser, and R. W. Zdarko

Subjects
Nuclear physics, Physics, Particle physics, Annihilation, Branching fraction, Higgs boson, Mass spectrum, General Physics and Astronomy, High Energy Physics::Experiment, Elementary particle, Limit (mathematics), Particle identification, Boson
Abstract

A search for monojet production in e/sup +/e/sup -/ annihilation has been performed at ..sqrt..s = 29 GeV with the MAC detector at PEP. No events beyond those expected from tau decays have been found. The result has been interpreted as an upper limit for Z/sup 0/ decays into monojets, giving an upper limit for the branching ratio of 0.5% at the 90% confidence level. This limit excludes an interpretation that the monojets discovered by Arnison et al. are due to Z/sup 0/ decays into light Higgs pairs.

Published
1985

19. Precise Measurements of the Leptonic Branching Ratios of the Tau Lepton

Author

Alexander Lincoln Read, Piero Giorgio Verdini, H. N. Nelson, Kwong Lau, D. E. Groom, J. C. Sleeman, W. T. Ford, J. R. Smith, R. B. Hurst, M. Piccolo, J. H. Moromisato, R. W. Coombes, H. R. Band, W. D. Shambroom, D. E. Wiser, D. M. Ritson, M. C. Delfino, von Goeler E, G. P. Goderre, B. K. Heltsley, R. Prepost, T. Maruyama, J. P. Venuti, N. Qi, W. W. Ash, Lippi I I, L. J. Rosenberg, E. Fernandez, T. L. Lavine, H.T. Blume, Peruzzi I I, Roy Weinstein, L. J. Moss, H. B. Wald, Tiziano Camporesi, R. W. Zdarko, R. Messner, Johnson, R. E. Leedy, M. W. Gettner, F. Muller, and G. B. Chadwick

Subjects
Physics, Nuclear physics, Particle physics, General Physics and Astronomy, Branching (polymer chemistry), Charged particle, Lepton, Universality (dynamical systems)
Abstract

Precise measurements are reported for the leptonic branching ratios of the T lepton from the reaction e+e+ T+Tobserved with the MAC detector operating at PEP. Results from samples in which one T decays into three charged particles and the other to e or /,L are B, = 0.180 f 0.009 f 0.006 and B, = 0.183f0.009f0.005. A sample of ep events gives Be-B, = 0.0288f0.0017f0.0019. With the assumption of e-p universality these results are combined to give B, = 0.178 f 0.005 which implies a T lifetime of (2.85 f 0.09) x lo-l3 sec. PACS numbers: 14.6O.Jj, 13.35.+s

Published
1985

20. Determination of the lifetime of bottom hadrons

Author

D. M. Ritson, T. Maruyama, F. Muller, R. de Sangro, M. Bosman, J. R. Smith, R. Messner, Elliott D. Bloom, H. B. Wald, D. E. Wiser, H. R. Band, J. Pyrlik, Kwong Lau, D. E. Groom, J. C. Sleeman, W. T. Ford, J. H. Moromisato, G. L. Godfrey, M. W. Gettner, G. P. Goderre, W. W. Ash, J.R. Johnson, R. E. Leedy, Roy Weinstein, L. J. Moss, I. Lippi, M. C. Delfino, T. L. Lavine, J. P. Venuti, L. J. Rosenberg, Alexander Lincoln Read, N. Qi, Tiziano Camporesi, R. W. Zdarko, H. N. Nelson, R. Prepost, M. Piccolo, W. D. Shambroom, G. B. Chadwick, I. M. Peruzzi, Piero Giorgio Verdini, E. von Goeler, and R. B. Hurst

Subjects
Systematic error, Nuclear physics, Physics, Quark, Particle physics, General Physics, Annihilation, Hadron, Physical Sciences, General Physics and Astronomy, Vertex detector, Full sample
Abstract

We have measured the mean lifetime of the hadrons containing b quarks that are produced in ${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$ annihilation at \ensuremath{\surd}s =29 GeV. We use the full sample of data collected by the MAC detector at the SLAC storage ring, PEP, including those recently acquired with a precision vertex detector. The result is ${\ensuremath{\tau}}_{b}$=[1.29\ifmmode\pm\else\textpm\fi{}0.20(stat) \ifmmode\pm\else\textpm\fi{}0.07(syst) ps]\ifmmode\times\else\texttimes\fi{}(1.00\ifmmode\pm\else\textpm\fi{}0.15), where the last factor is the systematic uncertainty in the scale.

Published
1987

21. Charm photoproduction cross section at 20 GeV

Author

R. N. Diamond, S. Tether, M. MacDermott, S. Isaacson, H. O. Cohn, E. L. Hart, Kazuo Hasegawa, D. H. Brick, W. D. Walker, R. C. Field, K.C. Moffeit, H. H. Bingham, J. Goldberg, T. Maruyama, H. B. Wald, T. C. Bacon, Yuying Wu, C. A. Woods, N. Fujiwara, H. Yuta, I. A. Pless, Vasken Hagopian, M. Rabin, C. K. Sinclair, P. Haridas, A. M. Shapiro, G. E. Kalmus, J. E. Brau, C. G. Wilkins, J. J. Murray, H. Rudnicka, G. T. Condo, H. J. Hargis, T. Hayashino, J. S. Chima, T. Kitagaki, A. P. T. Palounek, P. Rankin, W. A. Mann, S. Tanaka, Geoffrey Hall, F. Ochiai, Y. Yoshimura, Shlomo Dado, R. Sugahara, Koji Abe, W. Cameron, E. Ronat, J. Kent, D. C. Colley, R. K. Yamamoto, J. T. Carroll, E. Hafen, R. Erickson, A. V. Bevan, James Shank, T. Glanzman, K. Braune, G. P. Gopal, G. Yekutieli, J. Schneps, J. E. Lannutti, C. V. Cautis, K. Tamai, W. M. Bugg, T. Handler, A. Napier, R. Merenyi, D. Q. Huang, R. I. Hulsizer, J. N. Butler, B. Franek, Aharon Levy, S. Noguchi, M. Widgoff, D. P. Kelsey, M. Jobes, C. Milstene, A. T. Goshaw, R. A. Gearhart, George P Yost, S. J. Sewell, L. Berny, S. W. O'Neale, S. Wolbers, A. H. Rogers, T. Sato, J. Ballam, S. Yamashita, T. Fieguth, W. J. Robertson, L.R. Fortney, P. J. Dornan, Edwin R. Hancock, P. W. Lucas, Akira Yamaguchi, R. H. Milburn, A. Suzuki, and K. Takahashi

Subjects
Nuclear physics, Physics, Particle physics, Cross section (physics), Scattering, General Physics and Astronomy, Bubble chamber, Elementary particle, Charm (quantum number), Laser beams, Particle identification, Particle detector, Particle Physics - Experiment
Abstract

Forty-seven charm events have been observed in an exposure of the SLAC Hybrid Facility bubble chamber to a 20-GeV backward-scattered laser beam. Thirty-seven events survive all the necessary cuts imposed. Based on this number the total charm cross section is calculated to be ${63}_{\ensuremath{-}28}^{+33}$ nb.

Published
1983

22. Dentistry for Nigerians with special needs: an overview

Author

H. B. Waldman, F. A. Oredugba, and S. P. Oredugba

Subjects
Disabilities, Dental education, Nigeria, Economics, Dentistry, RK1-715
Abstract

There are approximately 25 million residents with disabilities in Nigeria. Social inclusion of individuals with disabilities is difficult since societal views of these persons are in terms of charity and welfare rather than functioning members of a community. While there are no national studies of the dental needs of individuals with disabilities in Nigeria, there are reports of local studies of patients with disabilities which indicate a greater incidence of management difficulties as well as the need for improved oral hygiene and restorative services. Nevertheless, a study of practitioner involvement in the care of individuals with disabilities reported limited preparation of dental students to provide service for this population. Some organizations, such as the Special Olympics Healthy Athletes Special Smiles and the Smile Train, have set up programmes, both educational and service, to address some of their oral health issues. It is recommended that there is a need to identify the availability of current dental service centers for individuals with disabilities, establish a national organization to stimulate an awareness of the varied needs of individuals with disabilities and real programs in schools to prepare dental students to care for individuals with disabilities. Examples of dental education accreditation standards in other countries are used as models for the improvement in the preparation of dental students to provide services for individuals with special needs.

Published
2010
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