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104 results on '"P. Lennert"'

1. The Omega RICH in the CERN hyperon beam experiment

Author: G. Wälder, O. Thilmann, H. W. Siebert, S.G. Gerassimov, Jürgen Engelfried, K. Martens, P. Lennert, U. Müller, W. Beusch, H. Rieseberg, V.J. Smith, M. Boss, Dave M Newbold, and W. Klempt
Subjects: Physics, Nuclear and High Energy Physics, Large Hadron Collider, Spectrometer, Physics::Instrumentation and Detectors, Hyperon, Omega, Particle detector, Nuclear physics, Antiproton, Antimatter, High Energy Physics::Experiment, Nuclear Experiment, Instrumentation, Cherenkov radiation
Abstract: The Omega RICH, a large-aperture detector for identification of secondary pions, kaons, and (anti) protons was in operation at the CERN Omega spectrometer facility between 1984 and 1994. Cherenkov photons from a 5 m long radiator were detected in drift chambers with quartz windows, using TMAE-loaded counting gases. The RICH was used by experiments WA69 and WA82, until 1988. It was then equipped with new drift chambers and mirrors and was in use since 1990 in experiments WA89 and WA94. The setup in the WA89 hyperon beam experiment is described in more detail and efficiencies, resolutions, and physics results are discussed.
Published: 1999

2. The Cosmic Ray Tracking (CRT) detector system

Author: M. Ulrich, G. Leffers, M. Panter, Joachim Heintze, Konrad Bernlöhr, U. Trunk, S. Gamp, T. Wolf, R. Zink, J. Knöppler, G. Hermann, Thomas Kihm, S. Polenz, P. Lennert, R. Eckmann, Werner Hofmann, and V. Matheis
Subjects: Physics, Nuclear and High Energy Physics, Muon, Time projection chamber, Physics::Instrumentation and Detectors, business.industry, Astrophysics::High Energy Astrophysical Phenomena, Track (disk drive), Detector, HEGRA, Cosmic ray, Tracking (particle physics), Nuclear physics, Air shower, Optics, High Energy Physics::Experiment, business, Instrumentation
Abstract: The Cosmic Ray Tracking (CRT) project represents a study on the use of tracking detectors of the time projection chamber type to detect secondary cosmic ray particles in extensive air showers. In reconstructing the arrival direction of the primary cosmic ray particles, the CRT detectors take advantage of the angular correlation of secondary particles with the cosmic rays leading to these air showers. In this paper, the detector hardware including the custom-designed electronics system is described in detail. A CRT detector module provides an active area of 2.5 m 2 and allows to measure track directions with a precision of 0.4°. It consists of two circular drift chambers of 1.8 m diameter with six sense wires each, and a 10cm thick iron plate between the two chambers. Each detector has a local electronics box with a readout, trigger, and monitoring system. The detectors can distinguish penetrating muons from other types of charged secondaries. A large detector array could be used to search for γ -ray point sources at energies above several TeV and for studies of the cosmic-ray composition. Ten detectors are in operation at the site of the HEGRA air shower array.
Published: 1996

3. Ageing effects observed in the CERN Omega RICH

Author: P. Lennert, H. Rieseberg, F. Faller, U. Müller, G. Wälder, H. W. Siebert, R. Michaels, K. Martens, and Jürgen Engelfried
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Large Hadron Collider, Hyperon, Analytical chemistry, Ultrasonic sensor, Instrumentation, Omega, Layer (electronics), Beam (structure), Anode, Pulse (physics)
Abstract: We report on the new drift chambers of the Omega RICH used in the hyperon beam experiment WA89 at the CERN-SPS and in the heavy-ion experiment WA94. After four data-taking runs in 1990/91/92 it was found that the anode wires of the chambers were coated with a smooth layer of 1 μm thickness. Pulse heights were found to be reduced considerably with respect to those observed on new wires. Washing with alcohol and water in an ultrasonic bath restored the original pulse heights. In 1993 the RICH is running again in experiment WA89.
Published: 1994

4. QCD coherence studies using two particle azimuthal correlations

Author: P. Singh, M. Hauschild, C. Markus, P. Paschievici, T. R. Wyatt, Silvia Arcelli, R. W. L. Jones, M. Hansroul, H. Przysiezniak, P. Le Du, J. C. Clayton, B. Panzer-Steindel, Sachio Komamiya, E. Ros, J. P. Martin, J. Hart, G. Beaudoin, G. Giacomelli, Andris Skuja, C. Wahl, J. D. Gillies, C. P. Howarth, C. H. Shepherd-Themistocleous, J. E. Pilcher, Tetsuro Mashimo, M. Jimack, John Allison, O. Schaile, R. J. Homer, D. Axen, A. Jawahery, S. De Jong, Gideon Bella, Tohru Takeshita, T. J. Smith, D. J. Miller, Shlomo Dado, T. Hilse, A. Simon, T. P. Kokott, Carla Sbarra, Otmar Biebel, G. Tysarczyk-Niemeyer, P. Mättig, O. Runolfsson, G. E. Richards, P. M. Watklins, F. C. Grant, D. G. Charlton, D. L. Wagner, P. Poffenberger, M. A. Whalley, F. S. Merritt, F. Lamarche, C. Moisan, J. P. Walker, Peter Sherwood, Georges Azuelos, W. Gorn, C. M. Hawkes, M. Cooper, Daniel Lellouch, X. C. Lou, R. Van Kooten, P. A. Elcombe, R. W. Springer, Alexander Wagner, D. Pitman, P. Teixeira-Dias, J. F. Kral, K. W. Bell, G. A. Bahan, Takehiko Mori, Claudio Grandi, N. I. Geddes, Max Weber, H. Deng, R. Humbert, G. D. Lafferty, H. Mes, P. Jovanovic, D. C. Imrie, A. Buijs, Giora Mikenberg, J. C. Hill, M. H. Lehto, Austin Ball, D. Menszner, I. P. Duerdoth, M. Yurko, Misao Sasaki, D. M. Strom, P. W. Jeffreys, B. C. Shen, I. J. Bloodworth, C. Jui, J. Hagemann, P. Igo-Kemenes, J. Ludwig, K. Runge, P. Bock, T. Mouthuy, A. M. Lee, Tatsuo Kawamoto, Alessandro Montanari, H. J. Burckardt, R. G. Kellogg, Margret Fincke-Keeler, G. Maringer, A. K. Honma, M. Settles, R. J. Hemingway, P. G. Estabrooks, D. L. Rees, J. Becker, John Hobbs, Stefano Marcellini, W. G. Scott, D. G. Fong, M. Foucher, G. J. VanDalen, A. D. Schaile, James Letts, H. Jeremie, R. E. Hughes-Jones, U. Maur, R. Kowalewski, G. P. Siroli, J. Gascon, H. von der Schmitt, P. Pfister, G. W. Wilson, A. Astbury, K. J. Anderson, D. Karlen, G. A. Snow, C. P. Ward, S. Orito, M. Rosvick, R. Mir, J. A. McKenna, C. Burgard, G. T. Zorn, S. Wotton, F. G. Oakham, G. Duckeck, V. H. Winterer, Christoph Schwick, O. Ganel, J. Mildenberger, Harold Nguyen, V. Gibson, M. J. Losty, R. Ströhmer, P. Berlich, L. Köpke, E. do Couto e Silva, A. J. Martin, P. Taras, A. Yeaman, A. M. Rossi, P. S. Wells, Marcello Mannelli, J. E. Duboscq, Mitsuaki Nozaki, T. Tsukamoto, M. J. Oreglia, B. W. Kennedy, H. M. Fischer, J. Goldberg, P. E.L. Clarke, J. Steuerer, N. K. Watson, R. F. McGowan, M. Jobes, U. Binder, A. Michelini, A. C. Janissen, J. M. Lorah, M. Coupland, B. Nellen, J. Banks, P. Scharff-Hansen, Kiyotomo Kawagoe, W. J. Collins, Randall Sobie, W. Mohr, P. Leblanc, H. M. Bosch, Wolfram Dietrich Zeuner, Paul Kyberd, F. K. Loebinger, N. J. Tresilian, S. Weisz, G. N. Patrick, J. W. Gary, S. Bougerolle, R. D. Heuer, Fabrizio Fabbri, H. O. Ogren, D. Van den plas, Richard Keeler, M. W. Redmond, Christoph Geich-Gimbel, A. M. Smith, G. Vasseur, C. K. Hargrove, T. W. Pritchard, S. Levergrün, A. Rollnik, J. M. Roney, B. Lorazo, J. R. Carter, H. G. Evans, D. R. Rust, M. J. Goodrick, F. Odorici, J. E. Conboy, N. Paz-Jaoshvili, Claude Leroy, P. Lennert, Phillip Allport, I. Cohen, J. P. Pansart, P. Weber, J. Kroll, A. Gaidot, F. X. Gentit, R. Yaari, M. Kuwano, T. Wlodek, M. Sproston, S. Bethke, B. Boden, D. A. Hinshaw, Marco Cuffiani, P. Routenburg, B. Poli, A. Pouladdej, N. Tesch, A. Dieckmann, Erez Etzion, Tara Shears, J. R. Batley, D. E. Plane, C. Y. Chang, Stefan Kluth, Shlomit Tarem, M. Morii, S. W. O'Neale, Stephen Hillier, Peter R Hobson, T. Behnke, S. Rossberg, C. J. Oram, Gideon Alexander, R. P. Middleton, Horst Breuker, Paolo Capiluppi, P. Schenk, Alan Watson, D. J.P. Dumas, P. M. Hattersley, W. R. Gibson, A. Beck, P. F. Harrison, E. Heflin, P. D. Acton, Stephen Lloyd, R. M. Brown, M. Tecchio, Lorne Levinson, N. Wermes, Ehud Duchovni, R. Shypit, Roger Barlow, G. G. Hanson, E.J. Prebys, M. S. Dixit, Frans Meijers, H. Ihssen, S. W. Gensler, T. Kobayashi, C. J. Virtue, G. M. Dallavalle, J. von Krogh, Dave Robinson, L. A. del Pozo, Michael Dittmar, G. Yekutieli, A. A. Carter, S. Schreiber, T. J. McMahon, J. Schwiening, R. K. Carnegie, J. A. Wilson, W. Schappert, S. Barnett, D. Hochman, N. J. Thackray, K. Stephens, J. R. McNutt, G. Quast, John Baines, D. R. Ward, G. Transtromer, J. G. Layter, and M. F. Turner
Subjects: Quantum chromodynamics, Physics, Particle physics, Physics and Astronomy (miscellaneous), Electron–positron annihilation, High Energy Physics::Phenomenology, Hadron, Monte Carlo method, Perturbative QCD, Parton, Nuclear physics, High Energy Physics::Experiment, Nuclear Experiment, Parton shower, Engineering (miscellaneous), Particle Physics - Experiment, Coherence (physics)
Abstract: From a sample of 146900 hadronicZ 0 decays recorded by the OPAL detector at LEP, we have studied the azimuthal correlations of particles in hadronic events. It is expected that these correlations are sensitive to interference effects in QCD. We have compared the data to QCD Monte Carlo models which include and which do not include interference effects. We find that the distributions of azimuthal correlations are not reproduced by the parton shower models we have tested unless interference effects are included, no matter which hadronisation scheme is used.
Published: 1993

5. Inclusive neutral vector meson production in hadronicZ 0 decays

Author: P. Igo-Kemenes, C. Moisan, J. P. Walker, J. Goldberg, P. Teixeira-Dias, G. Maringer, B. Nellen, H. Jeremie, R. E. Hughes-Jones, U. Maur, M. Hauschild, P. M. Hattersley, R. Mir, P. Leblanc, V. Gibson, J. M. Lorah, I. J. Bloodworth, D. C. Imrie, Kiyotomo Kawagoe, C. Markus, P. Paschievici, Sachio Komamiya, G. P. Siroli, Christoph Schwick, J. M. Roney, D. A. Hinshaw, P. Weber, E. Ros, H. Mes, I. P. Duerdoth, S. Schreiber, A. Astbury, T. J. McMahon, D. J. Miller, W. Mohr, B. C. Shen, H. G. Evans, E. do Couto e Silva, P. E.L. Clarke, M. J. Goodrick, I. Cohen, M. Jimack, M. Hansroul, M. Yurko, M. J. Oreglia, R. Van Kooten, P. W. Jeffreys, D. Pitman, T. P. Kokott, Carla Sbarra, John Allison, O. Ganel, A. J. Martin, J. Schwiening, R. K. Carnegie, A. K. Honma, W. G. Scott, J. Steuerer, F. G. Oakham, M. Settles, P. S. Wells, R. G. Kellogg, J. G. Layter, A. M. Lee, M. Jobes, U. Binder, A. D. Schaile, C. H. Shepherd-Themistocleous, M. F. Turner, T. Behnke, P. Scharff-Hansen, M. H. Lehto, M. Foucher, P. A. Elcombe, R. J. Homer, R. Kowalewski, Terry Richard Wyatt, J. C. Clayton, Stefano Marcellini, J. A. Wilson, James Letts, Margret Fincke-Keeler, M. Coupland, G. A. Snow, C. P. Ward, D. L. Rees, J. Becker, T. Mouthuy, G. N. Patrick, F. S. Merritt, Paul Kyberd, O. Schaile, G. W. Wilson, S. Wotton, W. Schappert, F. K. Loebinger, D. Axen, A. Jawahery, M. J. Losty, A. Skuja, D. Karlen, A. Simon, Otmar Biebel, J. Hart, A. M. Smith, V. H. Winterer, M. W. Redmond, G. T. Zorn, G. Tysarczyk-Niemeyer, G. E. Richards, D. G. Charlton, D. L. Wagner, R. Yaari, G. Vasseur, P. Pfister, C. M. Hawkes, M. Cooper, Daniel Lellouch, S. Bethke, Marco Cuffiani, P. Poffenberger, Richard Keeler, G. Beaudoin, J. D. Gillies, J. P. Martin, C. K. Hargrove, M. Manelli, H. Deng, R. Humbert, Peter Sherwood, B. Lorazo, R. W. Springer, Alexander Wagner, A. Rollnik, A. M. Rossi, P. Berlich, L. Köpke, Takehiko Mori, R. J. Barlow, M. Morii, Michael Dittmar, J. Hagemann, J. Ludwig, H. Przysiezniak, G. J. Van Dalen, G. Yekutieli, K. Runge, P. Bock, S. De Jong, Peter R Hobson, D. R. Rust, Tetsuro Mashimo, T. Tsukamoto, P. Lennert, S. Levegrün, A. Gaidot, M. Kuwano, T. Wlodek, K. Stephens, Claude Leroy, Tohru Takeshita, Shlomo Dado, J. R. McNutt, M. Sproston, J. P. Pansart, T. Kawamoto, J. A. McKenna, F. Lamarche, F. Odorici, N. Paz-Jaoshvili, C. Wahl, W. J. Collins, Erez Etzion, P. Routenburg, F. C. Grant, M. A. Whalley, R. J. Hemingway, A. A. Carter, Randall Sobie, G. D. Lafferty, J. Mildenberger, N. Tesch, A. Dieckmann, C. P. Howarth, T. Hilse, Harold Nguyen, X. C. Lou, S. Orito, Stefan Kluth, M. Rosvick, Shlomit Tarem, P. Jovanovic, R. F. McGowan, Austin Ball, O. Runolfsson, D. Menszner, G. Duckeck, R. Ströhmer, Georges Azuelos, J. E. Pilcher, G. Quast, John Baines, A. Buijs, D. M. Strom, S. Rossberg, W. Gorn, Alessandro Montanari, John Hobbs, Giora Mikenberg, H. O. Ogren, Claudio Grandi, C. J. Oram, G. A. Bahan, Tara Shears, J. F. Kral, K. W. Bell, S. W. O'Neale, D. R. Ward, C. Y. Chang, G. Transtromer, T. W. Pritchard, H. M. Bosch, R. P. Middleton, Christoph Geich-Gimbel, Max Weber, T. J. Smith, A. Yeaman, N. K. Watson, J. Banks, Wolfram Dietrich Zeuner, G. G. Hanson, N. J. Tresilian, P. Taras, J. C. Hill, Misao Sasaki, S. Weisz, R. D. Heuer, Mitsuaki Nozaki, D. G. Fong, Fabrizio Fabbri, P. Mättig, J. Kroll, Horst Breuker, D. Van den plas, J. Gascon, S. Barnett, G. Giacomelli, H. von der Schmitt, N. J. Thackray, E.J. Prebys, F. X. Gentit, J. von Krogh, J. E. Conboy, J. W. Gary, M. S. Dixit, Frans Meijers, J. E. Duboscq, Dave Robinson, L. A. del Pozo, A. Pouladdej, K. J. Anderson, C. Jui, N. I. Geddes, B. Boden, B. Poli, H. M. Fischer, A. Michelini, A. C. Janissen, J. R. Carter, D. Hochmann, Silvia Arcelli, Phillip Allport, P. Singh, Gideon Alexander, Paolo Capiluppi, P. Schenk, R. W. L. Jones, N. Wermes, Ehud Duchovni, R. Shypit, P. Le Du, B. Panzer-Steindel, H. Ihssen, S. W. Gensler, T. Kobayashi, C. J. Virtue, P. G. Estabrooks, Gideon Bella, H. J. Burckhart, Jacqueline Batley, P. M. Watkins, P. F. Harrison, P. D. Acton, Stephen Lloyd, M. Tecchio, D. E. Plane, Stephen Hillier, G. M. Dallavalle, Alan Watson, D. J.P. Dumas, S. Bougerolle, W. R. Gibson, A. Beck, E. Heflin, R. M. Brown, Lorne Levinson, and B. W. Kennedy
Subjects: Physics, Particle physics, Meson production, Physics and Astronomy (miscellaneous), Electron–positron annihilation, Hadron, Monte Carlo method, Nuclear physics, Pion, Mass spectrum, High Energy Physics::Experiment, Neutral vector, Ionization energy, Engineering (miscellaneous), Particle Physics - Experiment
Abstract: Results are reported of a study of neutral vector meson production in multihadronicZ0 decays in the OPAL experiment at LEP. Pions and kaons have been identified by specific ionisation energy loss andK±π∓ andK+K− mass spectra have been fitted, in bins of the scaled momentum variablexp, to combinations of resonance signals and non-resonant backgrounds. Rates are given forK*(892)° and o(1020), and production cross sections are compared to the predictions of Monte Carlo models. Overall multiplicities have been determined as 0.76±0.07±0.06K*(892)° and 0.086±0.015±0.010 o(1020) per hadronicZ0 decay (the quoted errors are respectively statistical and systematic). Momentum dependent distortions of the ππ mass spectra, possibly associated indirectly with Bose-Einstein effects, have prevented reliable measurement of the ρ(770)° cross section in this study.
Published: 1992

6. A study of charged particle multiplicities in hadronic decays of theZ 0

Author: W. R. Gibson, C. Ho, R. Mir, H. Mes, A. Beck, H. Oh, E. Heflin, Margret Fincke-Keeler, I. P. Duerdoth, R. M. Brown, Lorne Levinson, B. W. Kennedy, K. J. Anderson, S. Bougerolle, F. Lamarche, R. J. Hemingway, D. E. Plane, Stephen Hillier, G. M. Dallavalle, Alan Watson, D. J.P. Dumas, M. Jobes, K. Stephens, J. R. McNutt, N. C. Wood, M. Jimack, John Allison, J. Goldberg, P. Jovanovic, Austin Ball, D. Menszner, F. Odorici, U. Binder, G. A. Snow, C. P. Ward, P. Pfister, J. P. Martin, M. W. Moss, P. M. Hattersley, M. J. Oreglia, J. R. Carter, G. N. Patrick, Silvia Arcelli, C. Fukunaga, P. Scharff-Hansen, W. J. Larson, R. G. Kellogg, B. Holl, I. Zacharov, Horst Breuker, B. Nellen, Alessandro Montanari, P. A. Elcombe, D. J. Miller, O. Runolfsson, V. Gibson, G. Quast, S. De Jong, John Baines, P. Leblanc, A. Astbury, D. C. Imrie, S. Wotton, Phillip Allport, G. Beaudoin, John Hobbs, Stefano Marcellini, J. Banks, P. Igo-Kemenes, T. Mouthuy, A. M. Smith, O. Ganel, James Letts, M. Weymann, G. Maringer, H. Jeremie, A. J. Martin, J. L. Pinfold, Tohru Takeshita, R. E. Hughes-Jones, U. Maur, A. Simon, G. P. Siroli, P. S. Wells, M. Hauschild, D. R. Ward, Shlomo Dado, G. Vasseur, D. L. Rees, B. Lorazo, M. Hansroul, H. E. Stier, Claudio Grandi, F. S. Merritt, K. Riles, G. Transtromer, J. Becker, P. G. Estabrooks, G. T. Zorn, A. M. Rossi, S. Levegrün, M. Yurko, S. Weisz, R. D. Heuer, Fabrizio Fabbri, M. J. Goodrick, Otmar Biebel, D. G. Charlton, P. Paschievici, C. J. Virtue, Terry Richard Wyatt, M. Coupland, P. Debu, I. Cohen, J. Mildenberger, Harold Nguyen, N. K. Watson, B. B. Brabson, P. W. Jeffreys, D. Van den plas, C. K. Hargrove, X. C. Lou, Gideon Alexander, N. I. Geddes, P. E.L. Clarke, D. G. Fong, M. Couch, Richard Keeler, Paolo Capiluppi, P. Schenk, A. M. Lee, B. Boden, J. Gascon, Georges Azuelos, P. M. Watkins, B. Poli, H. von der Schmitt, H. Takeda, Claude Leroy, G. Eckerlin, Giora Mikenberg, J. P. Pansart, G. J. VanDalen, J. von Krogh, D. R. Rust, N. Wermes, H. M. Fischer, A. Michelini, F. C. Grant, J. A. McKenna, R. Humbert, M. A. Whalley, B. P. O'Neill, J. F. Kral, F. G. Oakham, A. C. Janissen, K. W. Bell, J. W. Gary, R. J. Homer, Ehud Duchovni, R. Shypit, P. Lennert, Max Weber, I. Wingerter, Marcello Mannelli, S. A. Robins, R. F. McGowan, D. E. Klem, P. Ashton, A. Buijs, Andris Skuja, J. C. Hill, H. Ihssen, H. O. Ogren, Dave Robinson, M. F. Turner, Christoph Geich-Gimbel, Kiyotomo Kawagoe, Misao Sasaki, B. C. Shen, Gideon Bella, Tetsuro Mashimo, P. Poffenberger, S. W. O'Neale, Peter R Hobson, S. W. Gensler, J. D. Gillies, Paul Kyberd, F. K. Loebinger, L. A. del Pozo, A. K. Honma, M. M. Deninno, W. G. Scott, J. Kroll, C. Moisan, H. J. Burckhart, O. Schaile, J. P. Walker, R. Yaari, T. Kobayashi, Jacqueline Batley, R. Van Kooten, D. Pitman, F. X. Gentit, Sachio Komamiya, T. Kawamoto, J. E. Conboy, M. H. Lehto, E. Ros, S. Bethke, Michael Dittmar, M. Ogg, R. Kowalewski, P. Teixeira-Dias, R. J. Barlow, W. Gorn, M. W. Redmond, Marco Cuffiani, G. Yekutieli, J. M. Roney, A. Pouladdej, W. J. Collins, Randall Sobie, S. Orito, M. Rosvick, G. A. Bahan, A. Rollnik, G. G. Hanson, A. A. Carter, A. Gaidot, D. Hochman, N. J. Thackray, G. D. Lafferty, M. Kuwano, P. Weber, T. P. Kokott, Rene Brun, M. J. Losty, J. Hart, M. Sproston, S. J. Pawley, C. Y. Chang, P. Berlich, Claus Kleinwort, L. Köpke, T. W. Pritchard, H. Tsukamoto, P. Routenburg, P. Taras, Mitsuaki Nozaki, C. Wahl, S. Schreiber, G. Giacomelli, Y. Yang, T. J. McMahon, A. Dieckmann, J. Schwiening, C. P. Howarth, P. F. Harrison, P. Singh, R. K. Carnegie, H. Przysiezniak, J. E. Pilcher, J. A. Wilson, P. D. Acton, Stephen Lloyd, R. W. L. Jones, E.J. Prebys, A. D. Schaile, W. Schappert, P. Le Du, H. Kreutzmann, B. Panzer-Steindel, M. S. Dixit, Frans Meijers, V. H. Winterer, S. R. Hou, J. M. Lorah, W. Mohr, J. G. Layter, G. Duckeck, R. Ströhmer, D. Strom, S. Sanghera, H. M. Bosch, Wolfram Dietrich Zeuner, D. A. Hinshaw, T. Behnke, D. Axen, A. Jawahery, G. Tysarczyk-Niemeyer, Peter Sherwood, R. W. Springer, Alexander Wagner, J. Hagemann, J. Ludwig, K. Runge, P. Bock, I. J. Bloodworth, M. Settles, G. W. Wilson, D. Karlen, T. J. Smith, P. Mättig, C. M. Hawkes, M. Cooper, Daniel Lellouch, Takehiko Mori, Erez Etzion, Gareth J. Barker, Shlomit Tarem, S. Rossberg, C. J. Oram, and R. P. Middleton
Subjects: Physics, Particle physics, Physics and Astronomy (miscellaneous), Electron–positron annihilation, Hadron, Multiplicity (mathematics), Charged particle, Sphericity, Nuclear physics, Log-normal distribution, Gamma distribution, High Energy Physics::Experiment, Parton shower, Engineering (miscellaneous)
Abstract: We present an analysis of multiplicity distributions of charged particles produced inZ 0 hadronic decays. The results are based on the analysis of 82941 events collected within 100 MeV of theZ 0 peak energy with the OPAL detector at LEP. The charged particle multiplicity distribution, corrected for initial-state radiation and for detector acceptance and resolution, was found to have a mean 〈n ch〉=21.40±0.02(stat.)±0.43(syst.) and a dispersionD=6.49±0.02(stat.)±0.20(syst.). The shape is well described by the Lognormal and Gamma distributions. A negative binomial parameterisation was found to describe the shape of the multiplicity distribution less well. A comparison with results obtained at lower energies confirms the validity of KNO(-G) scaling up to LEP energies. A separate analysis of events with low sphericity, typically associated with two-jet final states, shows the presence of features expected for models based on a stochastic production mechanism for particles. In all cases, the features observed in the data are well described by the Lund parton shower model JETSET.
Published: 1992

7. Cosmic ray tracking — a new approach to high-energy γ-astronomy

Author: D. Brecht, S. Gamp, W. Hofmann, T. Kihm, J. Knöppler, V. Matheis, M. Panter, R. Reimers, M. Rosales, C. Wiedner, R. Zink, M. Feuerstack, J. Heintze, P. Lennert, S. Polenz, and B. Stadler
Subjects: Nuclear and High Energy Physics, Instrumentation
Published: 1992

8. The RICH counter in the CERN hyperon beam experiment

Author: Jürgen Engelfried, W. Beusch, P. Lennert, Joachim Heintze, G. Wälder, H. W. Siebert, S.G. Gerassimov, S. Kluth, H. Rieseberg, U. Müller, K. Martens, S. Ljungfelt, and R. Michaels
Subjects: Physics, Wire chamber, Nuclear and High Energy Physics, Photon, Large Hadron Collider, Atmospheric pressure, Physics::Instrumentation and Detectors, Hyperon, Photoelectric effect, Charged particle, Particle detector, Nuclear physics, Volume (thermodynamics), Measuring instrument, High Energy Physics::Experiment, Detectors and Experimental Techniques, Atomic physics, Instrumentation, Cherenkov radiation, Beam (structure)
Abstract: The hyperon beam experiment WA89 at the CERN-SPS uses a ring imaging Cherenkov counter (RICH) for identification of secondaries from ∑ − N reactions. Cherenkov photons are generated in a 5 m long radiator volume filled with nitrogen at atmospheric pressure and detected in drift chambers. The drift chambers cover an active surface of 1.6 × 0.75 m 2 , with a maximum drift path of 41 cm. Photoelectrons are counted on 1280 wires with a pitch of 2.54 mm, equipped with multihit TDCs. The counting gas is ethane saturated with TMAE at 30°C. The counter was operated in two beam periods in 1990 and 1991. The spatial resolution of the chambers is better than 2 mm and under normal running conditions 14 photoelectrons per ring have been detected on average.
Published: 1992

9. A measurement of strange baryon production in hadronic Z0 decays

Author: P. Paschievici, D. Karlen, A. Dieckmann, R. Mir, G. P. Siroli, A. Astbury, R. Van Kooten, C. H. Shepherd-Themistocleous, M. Hansroul, T. W. Pritchard, A. Wagner, John Hill, Silvia Arcelli, B. Boden, D. Menszner, T. Mouthuy, Gideon Bella, G. Vasseur, S. De Jong, J. C. Clayton, H. J. Burckhart, Jacqueline Batley, C. Geich-Gimbel, S. Rossberg, D. J. Miller, R. K. Carnegie, P. S. Wells, P. E.L. Clarke, Terry Richard Wyatt, F. G. Oakham, G. T. Zorn, T. Hilse, L. Levinson, R. J. Homer, Kiyotomo Kawagoe, A. Beck, H. G. Evans, John Hobbs, Tohru Takeshita, M. Fincke-Keeler, M. J. Oreglia, F. C. Grant, T. Wlodek, M. A. Whalley, A. M. Rossi, T. Tsukamoto, P. Schenk, M. J. Goodrick, N. Tesch, A. K. Honma, F. S. Merritt, R. Humbert, C. J. Virtue, Sachio Komamiya, W. Mohr, A. Buijs, D. M. Strom, G. N. Patrick, J. Mildenberger, C. Schwick, Richard Keeler, D. Hochman, J. P. Martin, P. Routenburg, O. Ganel, E. Ros, J. P. Walker, K. Runge, M. J. Losty, A. C. Janissen, C. J. Oram, U. Binder, J. M. Roney, J. R. Carter, A. Simon, M. Cooper, A. Rollnik, P. Singh, J. F. Kral, G. Beaudoin, J. A. McKenna, N. Wermes, P. Pfister, B. Poli, R. M. Brown, P. W. Jeffreys, J. Hart, J. Becker, K. J. Anderson, P. Weber, A. J. Martin, Carla Sbarra, X. C. Lou, A. A. Carter, T. P. Kokott, K. Stephens, R. F. McGowan, A. Yeaman, G. E. Richards, C. K. Hargrove, T. Behnke, Misao Sasaki, E. Heflin, J. P. Pansart, A. Michelini, D. A. Hinshaw, C. Markus, Marco Cuffiani, H. O. Ogren, D. G. Charlton, D. L. Wagner, D. Lellouch, C. Y. Chang, I. J. Bloodworth, C. Moisan, P. Berlich, B. C. Shen, G. Tysarczyk-Niemeyer, P. M. Watkins, P. Igo-Kemenes, H. Deng, Harold Nguyen, H. Ihssen, P. Bock, V. Gibson, Mitsuaki Nozaki, R. E. Hughes-Jones, J. G. Layter, A. Gaidot, James D Gillies, S. Wotton, Stefan Kluth, D. J.P. Dumas, R. Kowalewski, J. Kroll, P. Le Du, John Baines, S. Schreiber, S. Bethke, J. Schwiening, B. W. Kennedy, Tara Shears, F. X. Gentit, N. I. Geddes, V. H. Winterer, J. E. Conboy, Richard J Hemingway, B. Panzer-Steindel, M. Settles, G. Duckeck, M. Coupland, P. D. Acton, M. Morii, T. Kawamoto, S. W. O'Neale, Peter R Hobson, H. Mes, O. Runolfsson, P. Lennert, U. Maur, M. Foucher, R. J. Barlow, C. Jui, D. Pitman, Horst Breuker, P. M. Hattersley, P. Poffenberger, S. Orito, C. Wahl, E. do Couto e Silva, P. Mättig, D. R. Ward, P. Teixeira-Dias, M. F. Turner, G. A. Snow, C. P. Ward, G. W. Wilson, M. Hauschild, I. P. Duerdoth, F. Lamarche, H. M. Bosch, D. C. Imrie, C. Leroy, J. Steuerer, G. G. Hanson, G. Alexander, S. Bougerolle, J. Hagemann, H. Przysiezniak, E. Etzion, B. Lorazo, G. Quast, P. Leblanc, G. Giacomelli, J. Goldberg, Wolfram Dietrich Zeuner, E.J. Prebys, R. Ströhmer, Claudio Grandi, T. J. Smith, W. J. Collins, S. Dado, N. K. Watson, F. K. Loebinger, G. D. Lafferty, D. Axen, Frans Meijers, J. M. Lorah, A. Jawahery, B. Nellen, D. E. Plane, C. M. Hawkes, Peter Sherwood, W. R. Gibson, Stephen Hillier, G. M. Dallavalle, R. W. Springer, A. M. Lee, Takehiko Mori, J. R. McNutt, K. W. Bell, R. P. Middleton, M. Weber, J. Ludwig, C. P. Howarth, M. W. Redmond, A. Pouladdej, J. Gascon, Alan Watson, P. G. Estabrooks, J. E. Pilcher, G. Mikenberg, G. Maringer, S. Barnett, R. Yaari, S. Tarem, O. Biebel, M. Jimack, N. J. Thackray, John Allison, A. D. Schaile, P. Jovanovic, P. A. Elcombe, R. G. Kellogg, Austin Ball, W. Schappert, F. Odorici, Stefano Marcellini, Alessandro Montanari, James Letts, D. L. Rees, G. J. VanDalen, N. Paz-Jaoshvili, M. Kuwano, G. Transtromer, W. G. Scott, P. F. Harrison, Stephen Lloyd, M. Tecchio, M. Yurko, R. Shypit, S. W. Gensler, T. Kobayashi, D. G. Fong, H. von der Schmitt, Phillip Allport, R. Sobie, H. Jeremie, J. W. Gary, Marcello Mannelli, J. E. Duboscq, M. Jobes, P. Kyberd, Paolo Capiluppi, P. Scharff-Hansen, A. M. Smith, Andris Skuja, Tetsuro Mashimo, W. Gorn, G. Yekutieli, M. Rosvick, G. A. Bahan, R. W.L. Jones, J. von Krogh, Dave Robinson, L. A. del Pozo, Michael Dittmar, H. M. Fischer, T. J. McMahon, O. Schaile, M. H. Lehto, E. Duchovni, J. A. Wilson, S. Levegrün, L. Köpke, I. Cohen, M. S. Dixit, J. Banks, G. Azuelos, N. J. Tresilian, S. Weisz, R. D. Heuer, Fabrizio Fabbri, D. Van den plas, D. R. Rust, M. Sproston, and P. Taras
Subjects: Quantum chromodynamics, Physics, Nuclear and High Energy Physics, Particle physics, Octet, High Energy Physics::Lattice, Electron–positron annihilation, Nuclear Theory, High Energy Physics::Phenomenology, Hadron, OPAL detector, Baryon, Nuclear physics, Momentum, Diquark, QCD predictions, High Energy Physics::Experiment, Strange baryons, Particle Physics - Experiment, Spin-½
Abstract: The production of the octet and decuplet baryons Λ, Ξ − , Σ (1385) ± , Ξ(1530) 0 and Ω − and the corresponding antibaryons has been measured in a sample of 485 000 hadronic Z 0 decays. Results on differential and integrated cross sections are presented. The differential cross section of Λ baryons is found to be softer than the one predicted by the Jetset and Herwig Monte Carlo generators. The measured decuplet yields are found to disagree with the simple diquark picture where only one tuning parameter for spin 1 diquarks is used. Comparisons of the momentum spectra for Λ and Ξ − with the predictions of an analytical QCD formula are also presented.
Published: 1992

10. A study of two-particle momentum correlations in hadronic Z0 decays

Author: M. Jimack, P. Igo-Kemenes, G. Maringer, Shlomo Dado, John Allison, H. Jeremie, D. J. Miller, F. Lamarche, R. J. Hemingway, D. E. Klem, Michael Dittmar, G. Yekutieli, P. S. Wells, A. A. Carter, R. E. Hughes-Jones, U. Maur, Terry Richard Wyatt, I. J. Bloodworth, X. C. Lou, R. G. Kellogg, P. Jovanovic, Horst Breuker, Erez Etzion, H. Mes, M. Coupland, Austin Ball, D. Menszner, F. C. Grant, P. G. Estabrooks, D. R. Rust, R. Mir, I. P. Duerdoth, M. A. Whalley, Stefano Marcellini, Gareth J. Barker, M. Settles, B. C. Shen, K. J. Anderson, Gideon Bella, Giora Mikenberg, Shlomit Tarem, P. E.L. Clarke, H. Oh, E. do Couto e Silva, Alessandro Montanari, James Letts, W. J. Collins, K. Stephens, J. Steuerer, A. K. Honma, P. Lennert, H. J. Burckhart, Randall Sobie, G. D. Lafferty, S. Rossberg, W. G. Scott, A. Buijs, C. Y. Chang, Jacqueline Batley, C. J. Oram, P. M. Watkins, H. O. Ogren, J. R. McNutt, M. Yurko, P. M. Hattersley, W. R. Gibson, P. Taras, Christoph Geich-Gimbel, T. W. Pritchard, G. W. Wilson, R. P. Middleton, N. I. Geddes, R. Kowalewski, J. Mildenberger, Harold Nguyen, D. Karlen, M. Hauschild, Glenn Patrick, P. W. Jeffreys, A. M. Lee, E. Ros, M. J. Oreglia, P. Paschievici, Kiyotomo Kawagoe, M. Hansroul, H. Takeda, M. M. Deninno, J. Goldberg, B. Boden, D. Axen, M. J. Losty, B. Nellen, F. G. Oakham, G. A. Snow, C. P. Ward, Silvia Arcelli, A. Jawahery, J. Kroll, B. Poli, N. Paz-Jaoshvili, P. Leblanc, J. M. Roney, Paul Kyberd, F. K. Loebinger, A. Beck, P. F. Harrison, T. J. Smith, J. Hart, F. X. Gentit, E. Heflin, G. Tysarczyk-Niemeyer, Richard Keeler, R. Yaari, J. E. Conboy, P. Weber, M. F. Turner, S. Bethke, A. D. Schaile, V. Gibson, Peter Sherwood, J. R. Carter, P. Poffenberger, G. Quast, M. Ogg, P. D. Acton, Stephen Lloyd, M. W. Redmond, Marco Cuffiani, H. G. Evans, J. Banks, J. P. Pansart, P. Mättig, R. M. Brown, Lorne Levinson, J. D. Gillies, A. Rollnik, A. Simon, D. G. Fong, Otmar Biebel, G. E. Richards, M. J. Goodrick, I. Cohen, N. J. Tresilian, J. G. Layter, John Baines, N. Wermes, A. Pouladdej, R. W. Springer, Alexander Wagner, Tohru Takeshita, V. H. Winterer, T. Mouthuy, S. Weisz, R. D. Heuer, D. G. Charlton, D. L. Wagner, J. Gascon, C. M. Hawkes, H. von der Schmitt, M. Cooper, P. Singh, Claude Leroy, B. W. Kennedy, Fabrizio Fabbri, M. Couch, Ehud Duchovni, R. Shypit, Daniel Lellouch, J. Hagemann, D. Van den plas, J. Ludwig, R. J. Barlow, D. C. Imrie, K. Runge, P. Bock, Takehiko Mori, S. R. Hou, C. Wahl, A. Astbury, T. P. Kokott, Rene Brun, Carla Sbarra, F. S. Merritt, H. Ihssen, R. J. Homer, R. Van Kooten, Georges Azuelos, D. Pitman, R. W. L. Jones, D. R. Ward, R. Humbert, M. H. Lehto, G. Transtromer, C. P. Howarth, S. W. Gensler, J. F. Kral, G. P. Siroli, K. W. Bell, P. Le Du, D. A. Hinshaw, Christoph Schwick, S. Wotton, T. Kobayashi, C. J. Virtue, Max Weber, C. Fukunaga, B. Panzer-Steindel, O. Ganel, J. E. Pilcher, S. Bougerolle, John Hobbs, Misao Sasaki, J. A. McKenna, A. M. Rossi, F. Odorici, T. Tsukamoto, T. Behnke, Phillip Allport, S. Sanghera, S. Levegrün, H. M. Fischer, R. F. McGowan, A. J. Martin, A. Michelini, A. C. Janissen, J. W. Gary, C. Moisan, J. P. Walker, G. Duckeck, R. Ströhmer, S. A. Robins, O. Runolfsson, D. Strom, P. Teixeira-Dias, D. E. Plane, G. T. Zorn, Marcello Mannelli, J. E. Duboscq, Stephen Hillier, P. Berlich, L. Köpke, H. M. Bosch, Wolfram Dietrich Zeuner, G. M. Dallavalle, K. Riles, Andris Skuja, J. P. Martin, T. Kawamoto, Gideon Alexander, Paolo Capiluppi, P. Schenk, S. Barnett, Alan Watson, D. J.P. Dumas, D. Hochman, N. J. Thackray, John Hill, Tetsuro Mashimo, C. K. Hargrove, S. De Jong, S. Orito, Claudio Grandi, M. Rosvick, W. Gorn, Margret Fincke-Keeler, G. A. Bahan, M. Jobes, U. Binder, P. Scharff-Hansen, H. Przysiezniak, P. Pfister, G. G. Hanson, A. M. Smith, G. Vasseur, B. Lorazo, G. Giacomelli, N. K. Watson, E.J. Prebys, M. S. Dixit, S. Komamiya, Frans Meijers, S. W. O'Neale, Peter R Hobson, J. M. Lorah, W. Mohr, A. Gaidot, M. Kuwano, T. Wlodek, M. Sproston, P. Routenburg, N. Tesch, A. Dieckmann, P. A. Elcombe, D. L. Rees, J. Becker, G. J. VanDalen, S. Schreiber, T. J. McMahon, J. Schwiening, R. K. Carnegie, J. A. Wilson, W. Schappert, J. von Krogh, Dave Robinson, L. A. del Pozo, and G. Beaudoin
Subjects: Physics, Quantum chromodynamics, Nuclear and High Energy Physics, Particle physics, Logarithm, High Energy Physics::Phenomenology, Monte Carlo method, Hadron, String (physics), Hadronization, Nuclear physics, Momentum, High Energy Physics::Experiment, Parton shower, Particle Physics - Experiment
Abstract: We report on a measurement of two-particle momentum correlations in hadronic decays of the Z 0 at LEP. These data are compared with recent analytic QCD calculations based on the summation of leading and next-to-leading logarithms, and with QCD Monte Carlo simulations. We find that the analytic calculations show the same general features as the data, but that the overall level of the correlations is not reproduced, suggesting that higher order or hadronization effects are significant. This contrasts with the success of similar QCD calculations in describing single-particle momentum distributions. QCD Monte Carlo models are found to give a reasonable level of correlation, with parton shower models incorporating string hadronization giving the best description of the data.
Published: 1992

11. A measurement of electron production in hadronicZ 0 decays and a determination of $$\Gamma (Z^0 \to b\bar b)$$

Author: A. Simon, Otmar Biebel, D. G. Charlton, D. L. Wagner, M. Couch, M. Hansroul, P. G. Estabrooks, R. K. Keeler, R. Humbert, Gideon Bella, H. J. Burckhart, D. Hochman, N. J. Thackray, J. Goldberg, Jacqueline Batley, A. Gaidot, B. Nellen, R. J. Homer, P. M. Watkins, P. Leblanc, P. E.L. Clarke, M. Kuwano, T. Wlodek, M. Sproston, W. J. Collins, Randall Sobie, T. Kawamoto, G. D. Lafferty, P. Routenburg, H. G. Evans, T. W. Pritchard, A. Dieckmann, T. Mouthuy, I. Wingerter, M. J. Goodrick, I. Cohen, A. Astbury, S. Orito, M. Rosvick, C. Fukunaga, S. Bougerolle, J. Hart, A. D. Schaile, C. Moisan, J. P. Walker, O. Ganel, A. J. Martin, Silvia Arcelli, V. H. Winterer, J. M. Lorah, Sachio Komamiya, P. Igo-Kemenes, G. Maringer, P. Teixeira-Dias, W. Mohr, A. M. Rossi, S. R. Hou, K. Riles, R. Mir, H. Jeremie, H. Oh, T. Tsukamoto, S. Levegrün, D. E. Klem, R. E. Hughes-Jones, U. Maur, J. von Krogh, W. R. Gibson, C. Ho, B. P. O'Neill, E. Ros, A. T. Watson, C. K. Hargrove, R. Yaari, R. Van Kooten, S. Wotton, P. Singh, Y. Yang, Margret Fincke-Keeler, P. Ashton, N. I. Geddes, A. Beck, S. Bethke, Marco Cuffiani, D. Pitman, P. A. Elcombe, E. Heflin, M. J. Oreglia, Dave Robinson, R. M. Brown, M. I. Losty, Lorne Levinson, P. F. Harrison, R. W. L. Jones, B. Boden, L. A. del Pozo, M. F. Turner, H. Mes, B. Poli, M. H. Lehto, P. Poffenberger, P. Pfister, P. D. Acton, Stephen Lloyd, K. Stephens, B. B. Brabson, J. R. McNutt, Horst Breuker, B. W. Kennedy, T. P. Kokott, Rene Brun, D. L. Rees, J. Becker, J. R. Carter, P. Le Du, H. Kreutzmann, B. Panzer-Steindel, D. G. Fong, B. C. Shen, J. Gascon, H. von der Schmitt, Erez Etzion, Phillip Allport, G. J. VanDalen, G. N. Patrick, Michael Dittmar, G. Yekutieli, I. P. Duerdoth, Gareth J. Barker, V. Gibson, G. Quast, Shlomit Tarem, H. M. Fischer, A. Michelini, A. C. Janissen, John Baines, D. E. Plane, S. Rossberg, C. J. Oram, A. K. Honma, A. A. Carter, Stephen Hillier, G. M. Dallavalle, S. A. Robins, R. P. Middleton, D. R. Ward, M. W. Moss, G. Transtromer, W. G. Scott, D. J.P. Dumas, Gideon Alexander, Paolo Capiluppi, P. Schenk, J. W. Gary, P. M. Hattersley, S. J. Pawley, Marcello Mannelli, S. Schreiber, Andris Skuja, C. Wahl, P. Berlich, L. Köpke, T. J. McMahon, C. Y. Chang, D. R. Rust, J. Schwiening, R. K. Carnegie, John Hobbs, N. Wermes, C. P. Howarth, Ehud Duchovni, R. Shypit, S. W. O'Neale, Peter R Hobson, P. Taras, R. Kowalewski, Tetsuro Mashimo, J. A. Wilson, P. Lennert, H. Ihssen, G. Beaudoin, W. Schappert, S. W. Gensler, E. do Conto el Silva, T. Kobayashi, W. Gorn, Shlomo Dado, J. E. Pilcher, H. Takeda, F. Odirici, J. Banks, S. Weisz, R. D. Heuer, N. K. Watson, Fabrizio Fabbri, D. Van den plas, F. G. Oakham, G. A. Bahan, M. Jobes, U. Binder, Claude Leroy, P. Scharff-Hansen, W. J. Larson, D. C. Imrie, M. Hauschild, F. Lamarche, G. P. Siroli, R. J. Hemingway, J. P. Pansart, X. C. Lou, P. Paschievici, A. M. Smith, G. Vasseur, B. Lorazo, P. Jovanovic, Austin Ball, Tohru Takeshita, D. Menszner, Alessandro Montanari, Giora Mikenberg, Kiyotomo Kawagoe, Georges Azuelos, J. F. Kral, K. J. Anderson, K. W. Bell, J. D. Gillies, P. S. Wells, C. J. Virtue, R. J. Barlow, Max Weber, Terry Richard Wyatt, J. M. Roney, P. Weber, D. J. Miller, J. C. Hill, Misao Sasaki, O. Schaile, M. Coupland, F. C. Grant, M. A. Whalley, N. C. Wood, A. Buijs, G. A. Snow, C. P. Ward, G. Duckeck, R. Ströhmer, D. Strom, G. T. Zorn, H. M. Bosch, Wolfram Dietrich Zeuner, D. Axen, A. Jawahery, G. Tysarczyk-Niemeyer, Peter Sherwood, R. W. Springer, Alexander Wagner, J. Hagemann, J. Ludwig, K. Runge, P. Bock, C. M. Hawkes, M. Cooper, Daniel Lellouch, D. A. Hinshaw, T. Behnke, Takehiko Mori, M. Yurko, P. W. Jeffreys, A. M. Lee, T. J. Smith, O. Runolfsson, P. Mättig, Claudio Grandi, I. J. Bloodworth, M. Settles, H. Przysiezniak, G. W. Wilson, D. Karlen, F. S. Merritt, J. A. McKenna, R. F. McGowan, H. O. Ogren, Christoph Geich-Gimbel, M. M. Deninno, J. Kroll, F. X. Gentit, J. E. Conboy, M. Ogg, J. Mildenberger, Harold Nguyen, A. Pouladdej, Paul Kyberd, F. K. Loebinger, M. W. Redmond, A. Rollnik, M. Jimack, John Allison, R. G. Kellogg, Stefano Marcellini, James Letts, G. G. Hanson, G. Giacomelli, E.J. Prebys, M. S. Dixit, Frans Meijers, J. G. Layter, S. Sanghera, J. P. Martin, S. De Jong, and P. Debu
Subjects: Physics, Quark, Semileptonic decay, Particle physics, Physics and Astronomy (miscellaneous), Branching fraction, Electron–positron annihilation, High Energy Physics::Phenomenology, Hadron, Electron, Nuclear physics, Transverse plane, High Energy Physics::Experiment, Nuclear Experiment, Engineering (miscellaneous), Production rate
Abstract: The production rate of electrons with momentump>4 GeV/c and large momentum transverse to the jet containing the electron has been measured in 136000 hadronic decays of theZ 0 recorded with the OPAL detector at LEP in 1990. The dominant source of these electrons is the semileptonic decay of hadrons containingb quarks. If we assume that the semileptonic branching fraction ofb hadrons produced on theZ 0 resonance is the same as the branching fraction measured at the ϒ(4S) resonance, we determine $$\Gamma _{b\bar b} = 394 \pm 13 \pm 32$$ MeV, where the first error is statistical and the second error is systematic. The sensitivity of the result to this assumption is discussed. We have reduced the dependence of our result on the model ofb hadron semileptonic decay by taking into account the correlation between the model dependence of the branching fractions measured at the ϒ(4S) and of our kinematic acceptance for electrons.
Published: 1992

12. Evidence for b-flavoured baryon production in Z0 decays at LEP

Author: J. Allison, G. Duckeck, R. Ströhmer, D. Strom, G. T. Zorn, G. G. Hanson, A. Astbury, C. Y. Chang, M. Yurko, P. W. Jeffreys, F. S. Merritt, B. C. Shen, H. M. Bosch, Wolfram Dietrich Zeuner, H. M. Fischer, J. Hart, P. Taras, O. Ganel, D. C. Imrie, A. M. Lee, Margret Fincke-Keeler, A. K. Honma, W. G. Scott, J. von Krogh, A. J. Martin, J. A. McKenna, P. G. Estabrooks, R. K. Keeler, A. Michelini, A. C. Janissen, G. Giacomelli, R. F. McGowan, R. Kowalewski, H. O. Ogren, Christoph Geich-Gimbel, E.J. Prebys, M. M. Deninno, J. Kroll, F. X. Gentit, J. E. Conboy, M. Ogg, P. Ashton, A. Pouladdej, K. Riles, P. Pfister, G. Beaudoin, G. P. Siroli, Dave Robinson, L. A. del Pozo, Y. Yang, R. Van Kooten, M. S. Dixit, Frans Meijers, R. Mir, S. A. Robins, D. Pitman, C. K. Hargrove, P. M. Watkins, H. Mes, H. Oh, P. F. Harrison, M. J. Losty, I. P. Duerdoth, M. H. Lehto, J. M. Lorah, Shlomo Dado, P. D. Acton, Stephen Lloyd, D. A. Hinshaw, Michael Dittmar, P. Igo-Kemenes, G. Maringer, D. E. Plane, W. Mohr, G. Yekutieli, J. G. Layter, B. B. Brabson, N. Wermes, D. G. Fong, Ehud Duchovni, M. F. Turner, H. Jeremie, M. Hansroul, P. Poffenberger, T. Mouthuy, Stephen Hillier, M. J. Oreglia, X. C. Lou, G. M. Dallavalle, K. Stephens, Paul Kyberd, F. K. Loebinger, J. R. McNutt, Kiyotomo Kawagoe, R. Shypit, T. Behnke, A. A. Carter, R. E. Hughes-Jones, U. Maur, Giora Mikenberg, Erez Etzion, S. Sanghera, J. Gascon, I. Wingerter, R. J. Homer, Tohru Takeshita, H. von der Schmitt, S. J. Pawley, P. Berlich, M. W. Redmond, J. M. Roney, H. Ihssen, D. J.P. Dumas, O. Schaile, John Hobbs, D. Axen, L. Köpke, P. Singh, Silvia Arcelli, A. Gaidot, Georges Azuelos, E. do Couto e Silva, S. W. Gensler, J. R. Carter, G. N. Patrick, A. Simon, Otmar Biebel, C. Moisan, J. P. Walker, M. Kuwano, T. Wlodek, P. Weber, M. Sproston, A. M. Rossi, J. P. Martin, P. Teixeira-Dias, S. Schreiber, A. Jawahery, G. Tysarczyk-Niemeyer, Peter Sherwood, T. J. McMahon, T. Kobayashi, D. E. Klen, Gareth J. Barker, D. G. Charlton, D. L. Wagner, M. Couch, T. Tsukamoto, S. Levegrün, V. Gibson, R. W. L. Jones, G. Quast, R. W. Springer, Alexander Wagner, Claude Leroy, A. Rollnik, J. F. Kral, P. Routenburg, K. W. Bell, J. Hagemann, J. Ludwig, K. Runge, A. Dieckmann, P. Bock, J. W. Gary, P. E.L. Clarke, J. P. Pansart, J. Banks, Max Weber, J. Schwiening, R. K. Carnegie, Shlomit Tarem, R. Humbert, G. A. Snow, C. P. Ward, S. De Jong, J. C. Hill, S. Weisz, J. A. Wilson, N. I. Geddes, R. D. Heuer, S. Bougerolle, F. Odorici, J. R. McMahon, Misao Sasaki, Fabrizio Fabbri, D. J. Miller, D. Van den plas, W. Schappert, B. Boden, T. Kawamoto, P. Debu, B. Poli, Horst Breuker, Phillip Allport, P. Le Du, H. Kreutzmann, B. Panzer-Steindel, John Baines, Marcello Mannelli, D. R. Rust, S. Orito, M. Rosvick, P. S. Wells, O. Runolfsson, J. Mildenberger, Harold Nguyen, M. Jobes, U. Binder, C. J. Virtue, S. Rossberg, G. D. Lafferty, C. J. Oram, P. Lennert, Gideon Alexander, Paolo Capiluppi, P. Schenk, W. R. Gibson, C. Ho, M. Coupland, Gideon Bella, H. J. Burckhart, P. Scharff-Hansen, Claudio Grandi, C. Wahl, D. R. Ward, R. Yaari, H. Takeda, A. Beck, G. Transtromer, E. Heflin, S. Bethke, W. J. Larson, R. M. Brown, Marco Cuffiani, Lorne Levinson, R. P. Middleton, M. W. Moss, Jacqueline Batley, F. C. Grant, M. Jimack, B. W. Kennedy, M. A. Whalley, K. J. Anderson, T. R. Wyatt, F. G. Oakham, P. M. Hattersley, R. J. Barlow, H. Przysiezniak, C. P. Howarth, R. G. Kellogg, B. P. O'Neill, S. Wotton, A. M. Smith, Stefano Marcellini, James Letts, G. Vasseur, J. Goldberg, A. Buijs, J. E. Pilcher, B. Lorazo, B. Nellen, P. Leblanc, Andris Skuja, I. J. Bloodworth, H. G. Evans, M. J. Goodrick, I. Cohen, Tetsuro Mashimo, M. Settles, D. Hochman, N. J. Thackray, M. Hauschild, A. D. Schaile, P. Paschievici, N. K. Watson, G. W. Wilson, D. Karlen, J. D. Gillies, G. A. Bahan, V. H. Winterer, T. J. Smith, P. Mättig, S. R. Hou, C. M. Hawkes, M. Cooper, Daniel Lellouch, N. C. Wood, Takehiko Mori, W. Corn, S. W. O'Neale, Peter R Hobson, Sachio Komamiya, E. Ros, A. T. Watson, C. Fukunaga, T. P. Kokott, Rene Brun, F. Lamarche, R. J. Hemingway, P. Jovanovic, Austin Ball, D. Menszner, Alessandro Montanari, W. J. Collins, Randall Sobie, T. W. Pritchard, P. A. Elcombe, D. L. Rees, J. Becker, and G. J. VanDalen
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Muon, Branching fraction, Electron–positron annihilation, High Energy Physics::Phenomenology, Hadron, Electron, Nuclear physics, Baryon, High Energy Physics::Experiment, Particle Physics - Experiment, Boson
Abstract: We observe evidence for the production of b-flavoured baryons in decays of the Z 0 boson with the OPAL detector at LEP. We find 68 Λl − , Λ l + candidates in 458 583 hadronic Z 0 decays. We interpret this as a signal of 55 ± 9 +0.3 −3.1 events from the semi-leptonic decays of b baryons. Assuming weakly decaying b baryons produced in Z 0 decays are mostly Λ b particles, we measure the product branching ratio (Γ b b /Γ had ) f ( b →Λ b ) B (Λ b →Λl − v X ) , averaged over the electron and muon channels, to be (6.2±1.0±1.5)×10 −4 .
Published: 1992

13. Test of CP-invariance in e+e−→Z0→τ+τ− and a limit on the weak dipole moment of the τ lepton

Author: D. J. Miller, B. B. Brabson, C. M. Hawkes, M. Cooper, Silvia Arcelli, Daniel Lellouch, Takehiko Mori, D. G. Fong, J. Gascon, Gideon Bella, H. von der Schmitt, H. J. Burckhart, Jacqueline Batley, P. S. Wells, C. J. Virtue, R. Mir, H. Oh, D. Axen, A. Jawahery, Terry Richard Wyatt, G. Beaudoin, T. Mouthuy, P. Singh, R. W. L. Jones, P. Le Du, H. Kreutzmann, B. Panzer-Steindel, M. Coupland, N. K. Watson, B. P. O'Neill, R. Van Kooten, P. E.L. Clarke, P. G. Estabrooks, R. K. Keeler, M. Hansroul, G. Tysarczyk-Niemeyer, J. W. Gary, F. C. Grant, M. A. Whalley, D. Pitman, M. H. Lehto, S. Wotton, P. M. Watkins, Marcello Mannelli, Shlomo Dado, Sachio Komamiya, M. Yurko, E. Ros, A. T. Watson, P. W. Jeffreys, Peter Sherwood, M. J. Oreglia, Phillip Allport, M. Jimack, John Allison, A. Buijs, B. C. Shen, R. W. Springer, Alexander Wagner, P. Igo-Kemenes, G. Maringer, R. J. Homer, I. Wingerter, M. W. Moss, T. P. Kokott, Rene Brun, T. J. Smith, H. O. Ogren, Christoph Geich-Gimbel, U. Biebel, A. M. Rossi, H. Jeremie, Andris Skuja, X. C. Lou, A. M. Lee, P. Mättig, J. Hagemann, S. J. Pawley, R. E. Hughes-Jones, U. Maur, J. Ludwig, A. K. Honma, A. Astbury, M. M. Deninno, K. Runge, P. Bock, O. Ganel, P. Berlich, L. Köpke, Tetsuro Mashimo, T. Tsukamoto, S. Levegrün, Giora Mikenberg, J. Kroll, J. M. Lorah, F. Odorici, R. G. Kellogg, A. J. Martin, W. G. Scott, E. do Couto e Silva, K. Riles, P. M. Hattersley, W. Mohr, I. J. Bloodworth, F. X. Gentit, H. M. Fischer, C. Moisan, J. R. Carter, D. C. Imrie, G. N. Patrick, J. P. Walker, S. Bougerolle, J. E. Conboy, M. Ogg, A. Michelini, M. Settles, C. Fukunaga, A. C. Janissen, R. Kowalewski, Stefano Marcellini, A. Pouladdej, J. Banks, R. Yaari, James Letts, S. Weisz, S. W. O'Neale, Peter R Hobson, P. Teixeira-Dias, F. Lamarche, A. Simon, S. Bethke, F. S. Merritt, R. D. Heuer, Fabrizio Fabbri, D. Van den plas, Marco Cuffiani, W. Gorn, Horst Breuker, G. P. Siroli, Erez Etzion, G. W. Wilson, Gareth J. Barker, G. A. Bahan, D. Karlen, D. R. Rust, M. Jobes, D. G. Charlton, D. L. Wagner, U. Binder, S. A. Robins, M. J. Losty, G. A. Snow, C. P. Ward, R. J. Hemingway, Claude Leroy, J. Mildenberger, C. Wahl, Harold Nguyen, Gideon Alexander, P. Lennert, J. P. Pansart, D. A. Hinshaw, Shlomit Tarem, A. Gaidot, J. A. McKenna, M. Kuwano, T. Wlodek, M. Couch, P. Scharff-Hansen, M. Sproston, W. J. Larson, R. F. McGowan, R. Humbert, Paolo Capiluppi, P. Schenk, H. Mes, I. P. Duerdoth, Kiyotomo Kawagoe, A. M. Smith, A. Dieckmann, John Hobbs, T. Behnke, Margret Fincke-Keeler, C. P. Howarth, G. Vasseur, B. Lorazo, S. Rossberg, W. R. Gibson, P. Routenberg, C. J. Oram, N. I. Geddes, P. Jovanovic, Tohru Takeshita, Paul Kyberd, F. K. Loebinger, J. M. Roney, Austin Ball, N. Wermes, P. A. Elcombe, R. P. Middleton, W. J. Collins, T. Kawamoto, C. K. Hangrove, Georges Azuelos, J. E. Pilcher, G. Duckeck, R. Ströhmer, B. Boden, C. Ho, M. W. Redmond, B. Poli, J. Goldberg, D. Strom, P. Weber, G. T. Zorn, Randall Sobie, G. D. Lafferty, A. Rollnik, D. Menszner, D. L. Rees, J. Becker, J. F. Kral, B. Nellen, Claudio Grandi, K. W. Bell, S. Orito, H. M. Bosch, Wolfram Dietrich Zeuner, Max Weber, M. Rosvick, P. Leblanc, G. J. VanDalen, J. C. Hill, Misao Sasaki, A. Beck, H. G. Evans, M. J. Goodrick, T. W. Pritchard, I. Cohen, E. Heflin, Ehud Duchovni, R. Shypit, R. M. Brown, Alessandro Montanari, Lorne Levinson, A. D. Schaile, B. W. Kennedy, V. H. Winterer, H. Ihssen, O. Runolfsson, J. D. Gillies, O. Schaile, S. R. Hou, D. E. Plane, R. J. Barlow, Stephen Hillier, G. M. Dallavalle, S. W. Gensler, M. Hauschild, D. J.P. Dumas, T. Kobayashi, P. Paschievici, H. Takeda, F. G. Oakham, J. Hart, J. von Krogh, P. Ashton, Dave Robinson, L. A. del Pozo, S. Schreiber, T. J. McMahon, Y. Yang, J. Schwiening, R. K. Carnegie, P. F. Harrison, J. A. Wilson, P. D. Acton, Stephen Lloyd, W. Schappert, Michael Dittmar, H. Przysiezniak, G. Yekutieli, A. A. Carter, P. Pfister, K. J. Anderson, C. Y. Chang, P. Taras, D. E. Klem, M. F. Turner, P. Poffenberger, D. Hochman, N. J. Thackray, K. Stephens, J. R. McNutt, V. Gibson, G. Quast, John Baines, D. R. Ward, G. Transtromer, G. G. Hanson, G. Giacomelli, E.J. Prebys, M. S. Dixit, Frans Meijers, J. P. Martin, S. De Jong, N. C. Wood, P. Debu, J. G. Layter, and S. Sanghera
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Dipole, Neutral current, Electron–positron annihilation, High Energy Physics::Phenomenology, Moment (physics), High Energy Physics::Experiment, Observable, Expectation value, Signature (topology), Lepton
Abstract: Using a sample of 5558 Z 0 → τ + τ − decays produced at LEP a direct test of CP -invariance in the neutral current reaction e + e − → τ + τ − is performed. Samples of events where eachy τ decays into a single particle have been isolated for the construction of CP -odd observables. Three different event classes are considered: lepton-lepton, lepton-hadron, and hadron-hadron. No evidence for a non-zero expectation value of the considered CP -observables and hence for CP -violation is observed. Quantitatively, we deduce from this null result an estimate on the weak dipole moment d τ (m 2 Z = (−4.5 ± 5.3 ± 1.4) × 10 −17 e cm for the lepton-lepton signature and d τ (m 2 Z = (1.4 ± 3.7 ± 1.3) × 10 −17 e cm for the hadron-hadron signature. Combining these results we place a limit with 95% confidence of | d τ |⩽7.0 × 10 −17 e cm.
Published: 1992

14. Particle identification with the OPAL jet chamber

Author: W. Mohr, P. Igo-Kemenes, A. Dieckmann, A. P. Wagner, D. Schaile, Claus Kleinwort, H. von der Schmitt, J. Ludwig, P. Bock, R. D. Heuer, P. Lennert, M. Hauschild, C. Wahl, and O. Schaile
Subjects: Physics, Nuclear and High Energy Physics, Jet (fluid), Charged particle, Particle identification, Nuclear physics, Momentum, Calibration, Specific energy, Particle, High Energy Physics::Experiment, Detectors and Experimental Techniques, Charged particle beam, Instrumentation
Abstract: The jet chamber of the OPAL experiment at the e+e−-collider LEP is designed to measure the momentum of charged particles as well as the specific energy loss in the chamber gas. In this paper, the calibration procedure for the energy loss measurement is described in detail. A resolution of 3–4% has been achieved allowing identification of particles with momenta up to 20 GeV/c in dense particle environments typical for events from Z0 decays.
Published: 1992

15. A global determination of $$\alpha _s (M_{Z^0 } )$$ at LEP

Author: John Hart, H. Mes, H. O. Ogren, Christoph Geich-Gimbel, R. Mir, H. Oh, Tohru Takeshita, I. P. Duerdoth, G. G. Hanson, M. W. Moss, Silvia Arcelli, D. Hochman, N. J. Thackray, Horst Breuker, M. M. Deninno, P. M. Hattersley, J. M. Lorah, J. Kroll, F. X. Gentit, G. Giacomelli, Georges Azuelos, W. Mohr, John Hobbs, J. E. Conboy, M. Ogg, H. Takeda, W. R. Gibson, F. G. Oakham, E.J. Prebys, N. Wermes, R. Van Kooten, J. F. Kral, K. W. Bell, C. Ho, D. C. Imrie, M. J. Oreglia, P. Igo-Kemenes, A. Pouladdej, G. Maringer, H. Jeremie, R. E. Hughes-Jones, U. Maur, Ehud Duchovni, C. J. Virtue, R. Shypit, M. S. Dixit, V. Gibson, E. do Couto e Silva, Max Weber, D. Pitman, M. H. Lehto, Frans Meijers, J. von Krogh, A. Beck, J. C. Hill, E. Heflin, Misao Sasaki, B. B. Brabson, A. Astbury, T. R. Wyatt, D. G. Fong, G. D. Lafferty, P. Ashton, M. Hauschild, F. Lamarche, G. P. Siroli, R. M. Brown, H. Ihssen, O. Ganel, J. Gascon, H. von der Schmitt, R. J. Barlow, R. J. Hemingway, P. Singh, A. J. Martin, Dave Robinson, P. E.L. Clarke, J. P. Martin, Lorne Levinson, F. S. Merritt, A. D. Schaile, D. Axen, H. Przysiezniak, P. Paschievici, A. Gaidot, M. Kuwano, T. Wlodek, B. C. Shen, M. Sproston, A. Jawahery, S. De Jong, I. J. Bloodworth, G. N. Patrick, L. A. del Pozo, P. S. Wells, S. W. Gensler, B. W. Kennedy, K. Riles, P. Jovanovic, F. Odorici, P. G. Estabrooks, A. K. Honma, J. W. Gary, R. K. Keeler, Kiyotomo Kawagoe, Austin Ball, W. G. Scott, A. Dieckmann, G. Tysarczyk-Niemeyer, V. H. Winterer, T. Kobayashi, S. J. Pawley, M. Yurko, Marcello Mannelli, D. Menszner, R. W. L. Jones, P. W. Jeffreys, P. A. Elcombe, P. Debu, M. Jobes, U. Binder, J. A. McKenna, Peter Sherwood, R. Kowalewski, Michael Dittmar, G. Yekutieli, A. Simon, Otmar Biebel, P. Berlich, C. K. Hargrove, J. M. Roney, P. M. Watkins, S. R. Hou, A. M. Lee, R. W. Springer, Alexander Wagner, S. Bougerolle, P. Scharff-Hansen, D. E. Klem, W. J. Larson, Alessandro Montanari, R. F. McGowan, L. Köpke, M. Coupland, R. Yaari, D. G. Charlton, D. L. Wagner, M. Couch, A. A. Carter, P. Weber, J. Hagemann, P. Le Du, H. Kreutzmann, J. G. Layter, G. Beaudion, B. Panzer-Steindel, J. Ludwig, S. Bethke, D. L. Rees, J. Becker, K. Runge, G. A. Snow, C. P. Ward, K. J. Anderson, P. Bock, I. Wingerter, Marco Cuffiani, R. Humbert, M. J. Losty, J. D. Gillies, M. F. Turner, G. J. VanDalen, C. Fukunaga, A. M. Smith, G. Vasseur, B. Lorazo, O. Schaile, N. C. Wood, F. C. Grant, M. A. Whalley, S. Sanghera, M. Settles, D. R. Rust, Gideon Bella, S. Schreiber, Y. Yang, Andris Skuja, D. J. Miller, D. E. Plane, T. J. McMahon, H. J. Burckhart, Jacqueline Batley, J. Schwiening, J. Allison, P. F. Harrison, T. Kawamoto, Tetsuro Mashimo, Stephen Hillier, N. K. Watson, G. M. Dallavalle, R. K. Carnegie, G. Duckeck, R. Ströhmer, J. A. Wilson, Shlomo Dado, D. Strom, P. D. Acton, Stephen Lloyd, W. Gorn, P. Lennert, S. Orito, G. T. Zorn, W. J. Collins, W. Schappert, M. Rosvick, O. Runolfsson, D. J.P. Dumas, X. C. Lou, G. A. Bahan, Randall Sobie, H. M. Bosch, Wolfram Dietrich Zeuner, A. Buijs, T. W. Pritchard, Sachio Komamiya, Giora Mikenberg, C. Y. Chang, Claudio Grandi, P. Taras, E. Ros, A. T. Watson, D. A. Hinshaw, Gideon Alexander, Paolo Capiluppi, P. Schenk, C. Wahl, T. Behnke, B. P. O'Neill, C. P. Howarth, G. W. Wilson, D. Karlen, J. E. Pilcher, J. Banks, S. Wotton, S. Weisz, R. D. Heuer, Fabrizio Fabbri, D. Van den plas, T. P. Kokott, Rene Brun, P. Poffenberger, T. J. Smith, Claude Leroy, J. P. Pansart, Erez Etzion, P. Mättig, Gareth J. Barker, C. M. Hawkes, M. Cooper, Daniel Lellouch, Takehiko Mori, Shlomit Tarem, S. Rossberg, C. J. Oram, S. W. O'Neale, Peter R Hobson, R. P. Middleton, J. Goldberg, B. Nellen, P. Leblanc, C. Moisan, J. P. Walker, H. G. Evans, P. Teixeira-Dias, M. J. Goodrick, I. Cohen, M. Hansroul, R. J. Homer, Margret Fincke-Keeler, J. Mildenberger, Harold Nguyen, P. Pfister, Paul Kyberd, F. K. Loebinger, M. W. Redmond, A. Rollnik, M. Jimack, P. Routenberg, N. I. Geddes, B. Boden, B. Poli, R. G. Kellogg, P. P. Allport, T. Mouthuy, Stefano Marcellini, K. Stephens, J. R. McNutt, James Letts, A. M. Rossi, G. Quast, T. Tsukamoto, John Baines, S. Levegrün, H. M. Fischer, D. R. Ward, A. Michelini, G. Transtromer, A. C. Janissen, S. A. Robins, and J. R. Carter
Subjects: Physics, Particle physics, Physics and Astronomy (miscellaneous), Branching fraction, Electron–positron annihilation, Hadron, Perturbative QCD, Observable, Parton, Nuclear physics, Renormalization, High Energy Physics::Experiment, Resummation, Engineering (miscellaneous)
Abstract: The value of the strong coupling constant, $$\alpha _s (M_{Z^0 } )$$ , is determined from a study of 15 different observables in hadronicZ 0 and τ decays. The study includes global event shape variables, jet production rates, energy correlations, theZ 0 line shape and decay asymmetries and the hadronic branching fraction of τ-leptons. Differences between the αs values from the different observables can be consistently attributed to unknown higher order contributions to the calculations. These uncertaities may be parametrized by variations of the renormalization scale and of the parton virtuality to which the data are corrected, separately for each observable, resulting in a consistent description of the event shapes, jet rates and energy correlations with the value $$\alpha _s (M_{Z^0 } ) = 0.122_{ - 0.005}^{ + 0.006} $$ in . The error is dominated by the theoretical uncertainties. Application of recent calculations which include the resummation of leading and next-to-leading logarithms to all orders for some observables confirm this result with a reduced sensitivity to renormalization scale variations. TheZ 0 line shapes and τ-lepton branching ratios yield $$\alpha _s (M_{Z^0 } ) = 0.148 \pm 0.021$$ and $$\alpha _s (M_{Z^0 } ) = 0.123_{ - 0.007}^{ + 0.006} $$ , respectively, in . These measurements and their uncertainties are entirely independent of each other and from event shape and jet observables; the good agreement of the resulting αs values thus constitutes an important consistency check of the reliability of perturbative QCD.
Published: 1992

16. Measurement of B00 mixing in hadronic Z0 decays

Author: Kiyotomo Kawagoe, O. Ganel, J. Gascon, D. Axen, J. M. Roney, P. Weber, A. Wagner, Andris Skuja, R. P. Middleton, P. Le Du, M. Hauschild, B. Panzer-Steindel, D. E. Plane, Tetsuro Mashimo, J. L. Pinfold, C. Y. Chang, Mitsuaki Nozaki, G. Beaudoin, Stephen Hillier, G. M. Dallavalle, H. Mes, R. Van Kooten, M. H. Lehto, Sachio Komamiya, W. Gorn, Phillip Allport, Tohru Takeshita, P. Poffenberger, A. Astbury, F. K. Loebinger, M. W. Redmond, T. Behnke, R. Mir, H. Oh, R. M. Brown, F. C. Grant, M. A. Whalley, G. J. Barker, G. Yekutieli, D. J.P. Dumas, G. Mikenberg, I. P. Duerdoth, F. S. Merritt, Paolo Capiluppi, G. A. Bahan, G. P. Siroli, J. F. Kral, A. K. Honma, P. R. Hobson, E. Ros, A. T. Watson, G. Vasseur, A. Buijs, M. W. Moss, O. Biebel, P. M. Hattersley, A. Gaidot, N. Wermes, X. C. Lou, E. Etzion, S. J. Pawley, O. Runolfsson, John Hobbs, J. P. Pansart, P. Berlich, Claus Kleinwort, L. Köpke, R. Shypit, D. E. Klem, M. Jobes, U. Binder, G. Alexander, G. Bella, P. E.L. Clarke, R. J. Hemingway, P. Scharff-Hansen, W. J. Larson, C. Ho, C. Geich-Gimbel, Max Weber, M. J. Oreglia, J. Schwiening, P. D. Acton, Claudio Grandi, S. A. Robins, H. Ihssen, N. J. Thackray, K. Stephens, D. A. Hinshaw, H. J. Burckhart, M. Cooper, J. A. McKenna, E. Heflin, J. C. Hill, Misao Sasaki, M. F. Turner, M. Jimack, Jacqueline Batley, J. von Krogh, A. M. Smith, S. W. Gensler, G. Maringer, A. M. Lee, Rene Brun, M. Hansroul, B. W. Kennedy, B. C. Shen, J. M. Lorah, J. Banks, C. Wahl, H. M. Fischer, J. D. Gillies, D. C. Imrie, N. C. Wood, S. Tarem, S. Weisz, B. Lorazo, P. Ashton, Dave Robinson, J. Goldberg, M. Coupland, R. D. Heuer, T. P. Kokott, W. Mohr, C. P. Howarth, J. R. Carter, John Allison, P. Jovanovic, Austin Ball, D. Menszner, R. G. Kellogg, T. J. Smith, L. A. del Pozo, J. E. Pilcher, T. J. McMahon, C. Leroy, Fabrizio Fabbri, R. W.L. Jones, D. Van den plas, V. Gibson, R. J. Homer, M. Rosvick, G. A. Snow, C. P. Ward, P. A. Elcombe, R. K. Carnegie, G. Azuelos, B. B. Brabson, P. Mättig, D. G. Fong, S. Schreiber, Alessandro Montanari, H. von der Schmitt, G. N. Patrick, T. Kobayashi, J. G. Layter, A. A. Carter, B. Poli, Stefano Marcellini, J. A. Wilson, D. Pitman, R. Kowalewski, P. Debu, John Baines, E. Duchovni, D. R. Rust, B. Nellen, M. Sproston, W. Schappert, D. L. Rees, J. Becker, S. Bethke, G. Quast, Marco Cuffiani, C. M. Hawkes, D. G. Charlton, James Letts, M. Couch, P. Schenk, P. Lennert, J. Hart, O. Schaile, P. Taras, J. W. Gary, C. J. Oram, C. Fukunaga, M. J. Losty, A. J. Martin, C. Moisan, Marcello Mannelli, G. J. VanDalen, D. R. Ward, R. Humbert, P. F. Harrison, K. J. Anderson, Takehiko Mori, Michael Dittmar, S. Sanghera, J. Hagemann, P. S. Wells, C. J. Virtue, N. I. Geddes, P. Pfister, A. Michelini, A. C. Janissen, Terry Richard Wyatt, P. W. Jeffreys, A. Jawahery, R. Yaari, M. Fincke-Keeler, R. J. Barlow, G. Tysarczyk-Niemeyer, D. J. Miller, J. Mildenberger, Harold Nguyen, W. R. Gibson, A. Simon, T. W. Pritchard, Y. Yang, T. Kawamoto, Peter Sherwood, F. Odorici, D. Lellouch, M. Kuwano, R. W. Springer, J. Ludwig, P. Routenburg, S. Orito, A. Dieckmann, K. Runge, P. Bock, F. Lamarche, N. K. Watson, I. Cohen, D. Hochman, B. Boden, M. Yurko, G. Eckerlin, S. De Jong, I. J. Bloodworth, J. P. Walker, P. Teixeira-Dias, T. Mouthuy, G. Duckeck, R. Ströhmer, A. Rollnik, L. Levinson, W. J. Collins, G. D. Lafferty, D. Strom, H. Takeda, G. T. Zorn, F. G. Oakham, R. F. McGowan, P. Paschievici, H. M. Bosch, G. W. Wilson, M. Settles, H. O. Ogren, A. M. Rossi, P. Leblanc, Wolfram Dietrich Zeuner, M. M. Deninno, J. Kroll, J. P. Martin, T. Tsukamoto, S. Dado, G. G. Hanson, J. E. Conboy, M. Ogg, H. Kreutzmann, A. Pouladdej, A. D. Schaile, G. Giacomelli, V. H. Winterer, S. W. O'Neale, E.J. Prebys, S. R. Hou, D. Karlen, M. S. Dixit, Frans Meijers, Silvia Arcelli, U. Maur, S. Wotton, M. Weymann, H. E. Stier, P. G. Estabrooks, P. M. Watkins, P. Kyberd, I. Wingerter, S. Rossberg, K. W. Bell, P. Igo-Kemenes, A. Beck, R. E. Hughes-Jones, W. G. Scott, K. Riles, H. Jeremie, P. Singh, C. K. Hargrove, B. Holl, S. Levegrün, I. Zacharov, R. Sobie, Horst Breuker, S. Bougerolle, R. K. Keeler, M. J. Goodrick, G. Transtromer, H. Przysieniak, J. R. McNutt, S. L. Lloyd, B. P. O'Neill, and F. X. Gentit
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Muon, Electron–positron annihilation, High Energy Physics::Phenomenology, Hadron, Electron, Jet (particle physics), Bottom quark, Nuclear physics, High Energy Physics::Experiment, Mixing (physics), Lepton
Abstract: From a sample of approximately 135 000 hadronic Z0 decays recorded with the OPAL detector, 1 536 events were selected with two lepton candidates, either electrons or muons. A signal for B0 B 0 mixing was observed using the sign of the lepton charge to tag the charge of the b quark in decaying b-flavoured hadrons. A flavour discriminating variable was constructed from the lepton momentum and its component perpendicular to the jet axis. By fitting the fraction of events in which the two lepton charges are of the same sign, as a function of this variable, the average mixing parameter was measured to be χ = 0.145+0.041-0.035 ± 0.018, where the first error is statistical and the second is systematic.
Published: 1992

17. An improved measuremebts of αS (MZ0) using energy correlations with the OPAL detector at LEP

Author: H. M. Fischer, P. A. Elcombe, T. Mouthuy, T. J. McMahon, P. Routenburg, M. Cooper, B. Poli, P. Igo-Kemenes, Sachio Komamiya, A. M. Rossi, P. Debu, T. Tsukamoto, A. Michelini, S. Sanghera, J. Schweining, B. C. Shen, E. Ros, A. T. Watson, I. P. Duerdoth, F. Lamarche, R. Yaari, M. F. Turner, Richard Keeler, P. Jovanovic, D. J.P. Dumas, M. Hansroul, H. Ihssen, Austin Ball, D. L. Rees, W. Schappert, H. O. Ogren, O. Biebel, M. Jimack, John Allison, B. P. O'Neill, A. J. Martin, Rene Brun, Alessandro Montanari, M. Coupland, Gideon Bella, G. Vasseur, R. Mir, A. Astbury, P. Berlich, P. Lennert, R. J. Homer, S. Bougerolle, D. R. Rust, M. W. Moss, M. Sproston, G. J. VanDalen, A. D. Schaile, A. M. Lee, P. Poffenberger, J. Kroll, P. M. Hattersley, K. Stephens, U. Binder, H. Oh, R. G. Kellogg, P. Taras, R. M. Brown, S. W. Gensler, G. Maringer, F. X. Gentit, B. Boden, P. Mättig, E. Etzion, B. B. Brabson, N. C. Wood, W. J. Collins, S. De Jong, J. E. Conboy, T. Kobayashi, H. J. Burckhart, Jacqueline Batley, C. Geich-Gimbel, R. E. Hughes-Jones, G. W. Wilson, D. G. Fong, H. von der Schmitt, D. Menszner, D. Axen, Stefano Marcellini, J. P. Walker, A. C. Janissen, D. Karlen, A. Dieckmann, G. J. Barker, R. K. Carnegie, James Letts, M. Fincke-Keeler, G. D. Lafferty, R. Sobie, G. P. Siroli, Phillip Allport, P. Paschievici, M. Kuwano, P. Teixeira-Dias, A. A. Carter, M. Ogg, Tohru Takeshita, N. K. Watson, P. Singh, R. Shypit, G. Transtromer, G. A. Snow, H. E. Stier, R. Van Kooten, O. Schaile, M. H. Lehto, H. M. Bosch, D. C. Imrie, F. Odorici, V. Gibson, J. L. Pinfold, F. S. Merritt, John Baines, A. Rollnik, F. K. Loebinger, K. W. Bell, C. P. Ward, Kiyotomo Kawagoe, A. Beck, D. E. Plane, W. R. Gibson, Stephen Hillier, M. J. Goodrick, H. Takeda, H. Jeremie, J. W. Gary, H. Kreutzmann, Marcello Mannelli, W. G. Scott, J. Becker, K. J. Anderson, P. S. Wells, P. E.L. Clarke, G. M. Dallavalle, K. Runge, J. P. Martin, T. W. Pritchard, H. Przysiezniak, A. Wagner, J. F. Kral, C. J. Virtue, H. Mes, Terry Richard Wyatt, G. Duckeck, Richard J Hemingway, C. J. Oram, J. M. Roney, O. Runolfsson, M. Jobes, F. G. Oakham, E. Duchovni, P. G. Estabrooks, P. Kyberd, C. K. Hargrove, J. A. McKenna, Paolo Capiluppi, M. W. Redmond, P. Pfister, J. C. Hill, D. R. Ward, F. C. Grant, M. A. Whalley, P. Schenk, P. Scharff-Hansen, S. W. O'Neale, Peter R Hobson, T. P. Kokott, J. Hart, G. Tysarczyk-Niemeyer, Claudio Grandi, C. Ho, W. J. Larson, D. Pitman, Misao Sasaki, R. F. McGowan, A. Pouladdej, Marco Cuffiani, J. M. Lorah, M. M. Dennino, G. Mikenberg, D. Lellouch, C. Y. Chang, S. Rossberg, P. Bock, A. Buijs, S. J. Pawley, E. Heflin, G. G. Hanson, J. P. Pansart, M. J. Oreglia, Y. Yang, N. I. Geddes, R. J. Barlow, G. Alexander, B. Holl, P. Weber, S. Levegrün, P. F. Harrison, Claus Kleinwort, L. Köpke, S. Tarem, A. Gaidot, S. R. Hou, D. J. Miller, R. Humbert, G. N. Patrick, W. Mohr, S. Bethke, P. D. Acton, B. W. Kennedy, M. Hauschild, John Hobbs, S. A. Robins, D. Hochman, C. Fukunaga, I. Zacharov, M. J. Losty, G. Giacomelli, Stephen Lloyd, M. Yurko, J. Mildenberger, E.J. Prebys, Horst Breuker, Mitsuaki Nozaki, P. W. Jeffreys, X. C. Lou, A. M. Smith, C. Wahl, T. Behnke, C. Leroy, M. S. Dixit, B. Lorazo, G. Quast, P. Leblanc, S. Dado, J. Banks, G. Azuelos, Frans Meijers, P. Le Du, S. Weisz, R. D. Heuer, J. R. Carter, B. Panzer-Steindel, Fabrizio Fabbri, D. A. Hinshaw, D. Van den plas, M. Weber, L. Levinson, B. Nellen, J. G. Layter, D. E. Klem, A. K. Honma, D. G. Charlton, O. Ganel, K. Riles, M. Couch, G. Eckerlin, G. Beaudoin, N. J. Thackray, Andris Skuja, Harold Nguyen, J. Ludwig, C. P. Howarth, R. Kowalewski, J. Gascon, J. E. Pilcher, S. Schreiber, T. Kawamoto, S. Orito, V. H. Winterer, Tetsuro Mashimo, P. M. Watkins, W. Gorn, G. Yekutieli, M. Rosvick, G. A. Bahan, I. Wingerter, Silvia Arcelli, S. Wotton, A. Simon, M. Weymann, N. Wermes, A. Jawahery, Peter Sherwood, R. W. Springer, J. R. McNutt, U. Maur, D. Strom, G. T. Zorn, Wolfram Dietrich Zeuner, R. Ströhmer, J. A. Wilson, I. Cohen, Michael Dittmar, R. W.L. Jones, J. von Krogh, P. Ashton, Dave Robinson, L. A. del Pozo, J. Goldberg, T. J. Smith, I. J. Bloodworth, C. Moisan, James D Gillies, M. Settles, J. Hagemann, C. M. Hawkes, Takehiko Mori, and R. P. Middleton
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, media_common.quotation_subject, Electron–positron annihilation, Monte Carlo method, Hadron, Asymmetry, Hadronization, Nuclear physics, Renormalization, Correlation function, High Energy Physics::Experiment, Perturbation theory (quantum mechanics), Particle Physics - Experiment, media_common
Abstract: We report on an improved measurement of the value of the strong coupling constant σs at the Z0 peak, using the asymmetry of the energy-energy correlation function. The analysis, based on second-order perturbation theory and a data sample of about 145000 multihadronic Z0 decays, yields αs(Mz0 = 0.118±0.001(stat.)±0.003(exp.syst.)−0.004+0.0009 (theor. syst.), where the theoretical systematic error accounts for uncertainties due to hadronization, the choice of the renormalization scale and unknown higher-order terms. We adjust the parameters of a second-order matrix element Monte Carlo followed by string hadronization to best describe the energy correlation and other hadronic Z0 decay data. The αs result obtained from this second-order Monte Carlo is found to be unreliable if values of the renormalization scale smaller than about 0.15 Ecm are used in the generator.
Published: 1992

18. Measurement of three-jet distributions sensitive to the gluon spin ine + e − annihilations at $$\sqrt s = 91$$ GeV

Author: Phillip Allport, P. W. Jeffreys, A. M. Lee, B. C. Shen, J. D. Hobbs, H. E. Stier, D. A. Hinshaw, G. G. Hanson, P. Tarras, H. Mes, P. G. Estabrooks, R. K. Keeler, A. Simon, J. D. Gillies, I. P. Duerdoth, G. Giacomelli, Gideon Alexander, H. Przysiezniak, C. Y. Chang, N. C. Wood, E.J. Prebys, Otmar Biebel, D. G. Charlton, W. G. Scott, Paolo Capiluppi, P. Schenk, R. J. Barlow, O. Runolfsson, T. Mouthuy, L. Lessard, F. S. Merritt, Mitsuaki Nozaki, P. M. Watkins, M. Couch, D. J. Miller, Claudio Grandi, R. Humbert, M. S. Dixit, Frans Meijers, R. Kowalewski, Margret Fincke-Keeler, M. Jimack, John Allison, N. Wermes, M. A. Whalley, G. A. Snow, C. P. Ward, J. T.M. Chrin, L. Janissen, C. Milstene, Ehud Duchovni, R. Shypit, M. J. Losty, P. Singh, S. Schreiber, B. B. Brabson, J. G. Layter, A. M. Rossi, D. G. Fong, T. Kawamoto, J. Gascon, Kiyotomo Kawagoe, I. Wingerter, B. P. O'Neill, F. Lamarche, G. Beaudoin, A. Buijs, A. P. Wagner, T. J. McMahon, R. G. Kellogg, P. Pfister, T. Tsukamoto, J. Hagemann, H. Ihssen, S. W. Gensler, R. W. L. Jones, S. Levegrün, H. M. Fischer, S. Orito, John H. Schwarz, H. von der Schmitt, W. R. Gibson, G. Duckeck, R. Mir, R. J. Hemingway, Silvia Arcelli, A. Michelini, J. M. Roney, D. Hochman, N. J. Thackray, T. J. Smith, C. Ho, D. Strom, G. T. Zorn, Stefano Marcellini, R. F. McGowan, T. Kobayashi, H. Oh, Shlomo Dado, S. Sanghera, R. K. Carnegie, K. Stephens, C. Fukunaga, P. Jovanovic, J. Goldberg, J. C. Armitage, P. Mättig, H. O. Ogren, J. A. Wilson, Christoph Geich-Gimbel, P. Igo-Kemenes, G. Maringer, F. Odorici, S. A. Robins, J. R. McNutt, Austin Ball, D. Menszner, Alessandro Montanari, H. M. Bosch, D. C. Imrie, Tohru Takeshita, M. M. Deninno, M. J. Oreglia, W. Schappert, H. Jeremie, P. Le Du, H. Kreutzmann, A. Beck, J. Mildenberger, Harold Nguyen, Marcello Mannelli, M. Jobes, U. Binder, E. Heflin, R. M. Brown, Wolfram Dietrich Zeuner, E. K. U. Gross, A. Gaidot, M. Kuwano, P. Scharff-Hansen, Lorne Levinson, C. M. Hawkes, M. Cooper, Daniel Lellouch, G. P. Siroli, B. Nellen, P. Leblanc, M. J. Goodrick, M. Sproston, B. Panzer-Steindel, R. E. Hughes-Jones, U. Maur, I. Cohen, J. Hart, V. Gibson, Y. Yang, P. F. Harrison, J. L. Pinfold, G. Eckerlin, Michael Dittmar, W. J. Larson, D. Axen, A. Jawahery, John Baines, B. W. Kennedy, Georges Azuelos, G. Tysarczyk-Niemeyer, J. Kroll, O. Schaile, F. X. Gentit, J. E. Conboy, S. W. O'Neale, Peter R Hobson, M. Ogg, M. Hansroul, J. R. Carter, K. W. Bell, G. N. Patrick, G. Yekutieli, Gideon Bella, Stephen Lloyd, J. W. Gary, Takehiko Mori, A. D. Schaile, Peter Sherwood, S. Wotton, H. Takeda, Max Weber, K. J. Anderson, J. C. Hill, R. W. Springer, M. Weymann, A. Pouladdej, H. J. Burckhart, D. E. Klem, A. A. Carter, Misao Sasaki, A. M. Smith, Jacqueline Batley, N. I. Geddes, J. Ludwig, K. Runge, G. Vasseur, P. Routenburg, D. R. Ward, F. G. Oakham, P. Bock, Erez Etzion, M. W. Moss, Paul Kyberd, F. K. Loebinger, B. Lorazo, V. H. Winterer, A. Dieckmann, P. M. Hattersley, S. Bougerolle, Andris Skuja, B. Poli, J. Banks, M. W. Redmond, S. R. Hou, Claude Leroy, Gareth J. Barker, Tetsuro Mashimo, J. P. Martin, R. J. Homer, A. Rollnik, S. De Jong, M. F. Turner, P. Poffenberger, J. P. Pansart, N. K. Watson, J. von Krogh, I. J. Bloodworth, P. A. Elcombe, Shlomit Tarem, C. Wahl, W. J. Collins, Sachio Komamiya, A. T. Watson, S. Weisz, P. Ashton, Dave Robinson, Randall Sobie, G. D. Lafferty, C. P. Howarth, W. Gorn, D. E. Plane, T. P. Kokott, Rene Brun, J. E. Pilcher, M. Settles, G. A. Bahan, Stephen Hillier, R. D. Heuer, C. Moisan, J. P. Walker, C. K. Hargrove, T. W. Pritchard, Fabrizio Fabbri, G. M. Dallavalle, P. Teixeira-Dias, S. Rossberg, P. S. Wells, M. Hauschild, C. J. Oram, D. J.P. Dumas, C. J. Virtue, P. Paschievici, Terry Richard Wyatt, D. Van den plas, G. W. Wilson, D. Karlen, M. Coupland, D. L. Rees, P. Debu, J. Becker, D. R. Rust, R. P. Middleton, G. J. VanDalen, P. Lennert, M. H. Letho, R. Van Kooten, J. M. Lorah, W. Mohr, S. J. Pawley, Claus Kleinwort, L. Köpke, X. C. Lou, P. G. Murphy, Giora Mikenberg, P. E.L. Clarke, T. Behnke, B. Holl, I. Zacharov, Horst Breuker, R. Yaari, S. Bethke, Marco Cuffiani, Gunter Quast, A. Astbury, O. Ganel, A. J. Martin, and K. Riles
Subjects: Physics, Particle physics, Physics and Astronomy (miscellaneous), Electron–positron annihilation, High Energy Physics::Phenomenology, Scalar (mathematics), Elementary particle, Jet (particle physics), Gluon, Nuclear physics, High Energy Physics::Experiment, Field theory (psychology), Quantum field theory, Engineering (miscellaneous), Spin-½
Abstract: Three-jet variables constructed from multi-hadronic events produced byZ0 decays are compared to theoretical calculations assuming a vector gluon or a hypothetical scalar gluon. The data yield conclusive direct evidence for the former case. The distributions of the reduced energy of the second-most energetic jet and of the cosine of the Ellis-Karliner angle are chosen to demonstrate this effect.
Published: 1991

19. Measurement of branching ratios and τ polarization from τ→eνν−,τ→μνν−,andτ→π(K)ν decays at LEP

Author: Gideon Bella, H. J. Burckhart, Jacqueline Batley, H. M. Fischer, A. Michelini, H. E. Stier, P. E.L. Clarke, J. Hart, Sachio Komamiya, P. G. Estabrooks, T. Behnke, Robin Middleton, C. Milstene, Erez Etzion, B. B. Brabson, S. A. Robins, Y. Yang, D. G. Fong, Andris Skuja, P. Schenk, A. D. Schaile, Tetsuro Mashimo, J. Gascon, W. Gorn, H. von der Schmitt, G. A. Bahan, T. P. Kokott, Rene Brun, Richard Keeler, Marcello Mannelli, Gareth J. Barker, M. Jobes, U. Binder, Shlomit Tarem, P. Scharff-Hansen, W. J. Larson, J. W. Gary, T. Kobayashi, F. Odorici, A. M. Smith, H. Takeda, G. N. Patrick, G. Vasseur, P. F. Harrison, J. R. Carter, B. Lorazo, P. M. Watkins, F. G. Oakham, M. F. Turner, A. M. Lee, J. D. Hobbs, Robert M Brown, F. L. Fabbri, S. Rossberg, K. Stephens, G. G. Hanson, Kiyotomo Kawagoe, N. C. Wood, R. Yaari, Paul Kyberd, S. Bethke, F. K. Loebinger, P. Singh, J. R. McNutt, Claude Leroy, J. P. Pansart, A. P. Wagner, N. Wermes, P. Igo-Kemenes, Marco Cuffiani, J. D. Gillies, B. Poli, V. H. Winterer, G. Giacomelli, I. Wingerter, M. W. Redmond, Ehud Duchovni, M. A. Whalley, R. W. L. Jones, H. Mes, I. P. Duerdoth, J. M. Roney, G. Maringer, F. S. Merritt, J. Goldberg, Tohru Takeshita, P. Pfister, E. K. U. Gross, G. A. Snow, E.J. Prebys, Silvia Arcelli, A. Rollnik, C. P. Ward, H. Ihssen, P. Le Du, A. Gaidot, D. R. Rust, S. W. O'Neale, Peter R Hobson, H. Jeremie, B. Nellen, R. E. Hughes-Jones, M. Kuwano, H. Kreutzmann, M. S. Dixit, B. Panzer-Steindel, S. W. Gensler, G. Mikenberg, A. Buijs, Georges Azuelos, J. C. Armitage, Frans Meijers, S. R. Hou, L. Janissen, T. Mouthuy, D. E. Klem, U. Maur, P. Leblanc, D. J. Miller, Ken W Bell, John Baines, M. Sasaki, P. Lennert, V. Gibson, P. Routenburg, Max Weber, J. G. Layter, C. Moisan, R. J. Barlow, H. Przysiezniak, J. Mildenberger, J. P. Walker, D. E. Plane, M. J. Goodrick, I. Cohen, J. C. Hill, P. Teixeira-Dias, R. F. McGowan, N. K. Watson, A. Dieckmann, Harold Nguyen, B. C. Shen, Stephen Hillier, F. Lamarche, Gunter Quast, G. M. Dallavalle, R. J. Hemingway, N. I. Geddes, Shlomo Dado, D. R. Ward, Phillip Allport, S. Wotton, S. Bougerolle, W. J. Collins, H. O. Ogren, Christoph Geich-Gimbel, G. J. VanDalen, B. P. O'Neill, D. J.P. Dumas, R. Van Kooten, M. H. Lehto, S. Sanghera, O. Runolfsson, M. Weymann, M. W. Moss, M. Sproston, P. S. Wells, M. M. Deninno, J. Kroll, G. Eckerlin, R. Sobie, P. Jovanovic, W. G. Scott, C. J. Virtue, A. M. Rossi, T. Tsukamoto, S. L. Lloyd, C. J. Oram, F. X. Gentit, Austin Ball, P. W. Jeffreys, R. Kowalewski, M. Jimack, G. D. Lafferty, X. C. Lou, W. R. Gibson, Terry Richard Wyatt, A. T. Watson, J. Hagemann, P. M. Hattersley, M. Coupland, J. E. Conboy, D. Menszner, J. P. Martin, M. Ogg, C. Ho, S. J. Pawley, C. Wahl, J. M. Lorah, Gideon Alexander, K. J. Anderson, Alessandro Montanari, T. J. Smith, S. De Jong, A. Beck, E. Heflin, Paolo Capiluppi, T. W. Pritchard, Claus Kleinwort, Claudio Grandi, L. Köpke, A. Pouladdej, R. G. Kellogg, Lorne Levinson, O. Schaile, D. C. Imrie, B. Holl, W. Mohr, M. Hansroul, C. P. Howarth, M. J. Losty, L. Lessard, C. Y. Chang, B. W. Kennedy, Gilles Beaudoin, Stefano Marcellini, P. Debu, J. E. Pilcher, G. P. Siroli, J. Banks, P. Taras, Mitsuaki Nozaki, P. A. Elcombe, I. Zacharov, S. Weisz, R. D. Heuer, D. Van den plas, Horst Breuker, C. Fukunaga, D. Hochman, N. J. Thackray, D. L. Rees, J. Becker, M. Hauschild, R. J. Homer, P. Paschievici, A. Astbury, J. L. Pinfold, O. Ganel, A. J. Martin, K. Riles, P R Poffenberger, C. K. Hargrove, S. Levegrün, S. Schreiber, R. Mir, H. Oh, T. J. McMahon, J. Allison, G. Duckeck, D. Strom, G. T. Zorn, H. M. Bosch, R. K. Carnegie, Wolfram Dietrich Zeuner, J. A. Wilson, D. Axen, A. Jawahery, G. Tysarczyk-Niemeyer, M. Fincke-Keeler, P. G. Murphy, M. J. Oreglia, Peter Sherwood, R. W. Springer, J. Ludwig, K. Runge, P. Bock, W. Schappert, D. A. Hinshaw, A. Simon, Otmar Biebel, D. G. Charlton, M. Couch, R. Humbert, J. T.M. Chrin, T. Kawamoto, S. Orito, John H. Schwarz, Michael Dittmar, G. Yekutieli, A. A. Carter, P. Mättig, I. J. Bloodworth, M. Settles, J. von Krogh, G. W. Wilson, P. Ashton, Dave Robinson, D. Karlen, C. M. Hawkes, M. Cooper, Daniel Lellouch, R. Shypit, and Takehiko Mori
Subjects: Nuclear physics, Physics, Coupling constant, Nuclear and High Energy Physics, Pion, Muon, Electron–positron annihilation, Weinberg angle, Electron, Pseudovector, Lepton
Abstract: From a sample of 3308 e + e − → τ + τ − events with an estimated background of 1.9%, we find 964 τ → e ν ν , 903 τ → μν ν , and 309 τ → π( K )ν candidates. Efficiency and background estimates determined from both Monte Carlo and control sample studies yield the following branching ratios: B(τ → e ν ν ) = 17.4 ± 0.5 ( stat ) ± 0.4 ( sys )% , B(τ → μν ν ) = 16.8 ± 0.5 ± 0.4%, and B(τ → π( K )ν) = 12.1 ± 0.7 ± 0.5% . These values are in good agreement with previous measurements. The measured lepton branching ratios, when combined with the world-average measured value for the τ lifetime, yield a ratio of the τ Fermi coupling constant to that of the lighter leptons given by G τ / G e, μ = 0.92 ± 0.04, where it is assumed G e = G μ ≡ G e , μ . The average τ polarization at the Z° resonance is measured to be −0.01±0.09 from an analysis of the momentum spectra of the electron, muon, and pion candidates, implying that the ratio of vector to axial vector couplings of the τ to the Z° is ν τ / α τ = 0.01 ± 0.04. The measurements of the average polarizations in the forward and backward hemispheres lead to the efficiency-corrected, forward-backward polarization asymmetry A FB pol = −0.22 ± 0.10, implying for the electron couplings to the Z° the ratio ν e / α e = 0.15±0.07. Since these values for the tau and electron couplings are consistent with one another, we assume lepton universality to derive ν / α = 0.05 ± 0.04 and a value for the weak mixing angle of sin 2 θ W = 0.237 ± 0.009 , with no ambiguity introduced by the relative signs of ν and α.
Published: 1991

20. A search for scalar leptoquarks in Z0 decays

Author: H. E. Stier, P. G. Estabrooks, Erez Etzion, Gareth J. Barker, N. I. Geddes, P. Schenk, A. D. Schaile, Shlomit Tarem, P. M. Watkins, H. Mes, Kiyotomo Kawagoe, S. Rossberg, I. P. Duerdoth, V. H. Winterer, Tohru Takeshita, I. Wingerter, O. Schaile, A. P. Wagner, R. P. Middleton, B. Poli, S. R. Hou, J. M. Roney, Georges Azuelos, G. Beaudoin, L. Janissen, D. J. Miller, K. W. Bell, Max Weber, Misao Sasaki, H. O. Ogren, J. Goldberg, B. C. Shen, Shlomo Dado, H. Takeda, M. Hansroul, Christoph Geich-Gimbel, B. Nellen, N. Wermes, C. Milstene, P. Leblanc, F. Odorici, W. G. Scott, P. S. Wells, F. G. Oakham, C. J. Virtue, O. Runolfsson, X. C. Lou, P. G. Murphy, M. M. Deninno, Terry Richard Wyatt, B. Holl, J. Kroll, R. J. Homer, R. Kowalewski, L. Lessard, Andris Skuja, S. W. O'Neale, Ehud Duchovni, M. Coupland, T. J. Smith, F. X. Gentit, J. E. Conboy, J. D. Gillies, M. Ogg, M. J. Losty, Peter R Hobson, Giora Mikenberg, Silvia Arcelli, Claudio Grandi, P. Igo-Kemenes, D. C. Imrie, Richard Keeler, P. Mättig, I. Zacharov, C. Y. Chang, M. J. Goodrick, A. Pouladdej, I. Cohen, Tetsuro Mashimo, P. Singh, T. Mouthuy, C. Moisan, J. P. Walker, Horst Breuker, R. J. Barlow, G. Maringer, H. Ihssen, H. Jeremie, K. Stephens, C. Fukunaga, C. M. Hawkes, M. Cooper, Daniel Lellouch, R. Shypit, Takehiko Mori, G. K. VanDalen, P. W. Jeffreys, R. Van Kooten, F. S. Merritt, J. R. McNutt, G. P. Siroli, J. D. Hobbs, Claude Leroy, C. Wahl, P. Taras, S. W. Gensler, J. P. Pansart, R. W. L. Jones, N. C. Wood, W. Gorn, R. E. Hughes-Jones, U. Maur, Mitsuaki Nozaki, A. M. Lee, G. G. Hanson, F. Lamarche, D. E. Plane, R. J. Hemingway, Stephen Hillier, P. Le Du, H. Kreutzmann, B. Panzer-Steindel, V. Gibson, M. H. Lehto, M. A. Whalley, G. A. Bahan, J. Mildenberger, Harold Nguyen, Gunter Quast, S. Wotton, T. Kobayashi, G. M. Dallavalle, John Baines, Margret Fincke-Keeler, I. J. Bloodworth, C. P. Howarth, P. Jovanovic, E. K. U. Gross, A. Gaidot, M. Kuwano, Gideon Bella, H. J. Burckhart, N. K. Watson, M. Sproston, G. A. Snow, C. P. Ward, B. B. Brabson, M. Weymann, A. Buijs, J. E. Pilcher, Austin Ball, G. Giacomelli, J. Hart, E.J. Prebys, A. M. Rossi, D. E. Klem, D. R. Ward, M. Settles, D. Menszner, R. F. McGowan, D. G. Fong, Sachio Komamiya, Jacqueline Batley, B. P. O'Neill, Alan Watson, D. J.P. Dumas, P. Pfister, J. L. Pinfold, A. Astbury, J. Gascon, T. Tsukamoto, H. von der Schmitt, Alessandro Montanari, M. W. Moss, O. Ganel, S. Levegrün, H. M. Fischer, A. J. Martin, M. F. Turner, Y. Yang, P. Routenburg, P. M. Hattersley, T. P. Kokott, Rene Brun, J. Hagemann, J. C. Armitage, G. W. Wilson, D. Karlen, K. Riles, G. Eckerlin, M. S. Dixit, Frans Meijers, C. J. Oram, W. R. Gibson, P. F. Harrison, S. Bougerolle, W. J. Collins, S. J. Pawley, C. Ho, Marcello Mannelli, A. Michelini, Paul Kyberd, F. K. Loebinger, C. K. Hargrove, Stephen Lloyd, M. Jobes, U. Binder, D. Hochman, N. J. Thackray, P. Scharff-Hansen, G. D. Lafferty, A. Dieckmann, Claus Kleinwort, P. A. Elcombe, L. Köpke, W. J. Larson, P. Teixeira-Diaz, H. Przysiezniak, D. R. Rust, M. W. Redmond, J. W. Gary, T. W. Pritchard, J. G. Layter, A. Beck, A. Rollnik, A. M. Smith, P. E.L. Clarke, T. Behnke, E. Heflin, G. Vasseur, B. Lorazo, P. Lennert, Phillip Allport, R. M. Brown, S. Sanghera, M. Hauschild, S. A. Robins, R. Sobie, M. Jimack, John Allison, J. P. Martin, Gideon Alexander, Lorne Levinson, Paolo Capiluppi, K. J. Anderson, John Hill, P. Paschievici, B. W. Kennedy, S. De Jong, R. G. Kellogg, J. Banks, D. L. Rees, J. Becker, R. Yaari, S. Weisz, R. D. Heuer, Fabrizio Fabbri, D. Van den plas, S. Bethke, Marco Cuffiani, Stefano Marcellini, P. Debu, P R Poffenberger, J. M. Lorah, W. Mohr, D. Axen, A. Jawahery, G. Tysarczyk-Niemeyer, Peter Sherwood, R. W. Springer, Michael Dittmar, G. Yekutieli, J. Ludwig, K. Runge, P. Bock, A. Simon, Otmar Biebel, D. G. Charlton, M. Couch, R. Humbert, G. Duckeck, A. A. Carter, J. T.M. Chrin, D. Strom, G. T. Zorn, H. M. Bosch, T. Kawamoto, Wolfram Dietrich Zeuner, S. Orito, John H. Schwarz, D. A. Hinshaw, R. Mir, H. Oh, M. J. Oreglia, J. R. Carter, G. N. Patrick, J. von Krogh, P. Ashton, Dave Robinson, S. Schreiber, T. J. McMahon, R. K. Carnegie, J. A. Wilson, and W. Schappert
Subjects: Quark, Physics, Nuclear and High Energy Physics, Particle physics, Branching fraction, Electron–positron annihilation, High Energy Physics::Phenomenology, Scalar (physics), Nuclear physics, High Energy Physics::Experiment, Leptoquark, Neutrino, Particle Physics - Experiment, Storage ring, Lepton
Abstract: A search for scalar leptoquarks has been performed with data from the OPAL detector at the e+e− storage ring LEP. In a data sample corresponding to an integrated luminosity of 6.3 pb−1 no evidence for leptoquark production was observed where the leptoquark decays into a quark and either a charged lepton (e, μ, τ) or a neutrino. An upper limit of 1.7 pb on the production cross section for leptoquarks is obtainedassuming a branching ratio of 50% for the decay of the leptoquark into the channels with a charged lepton. Lower limits on the leptoquark mass between 41.4 and 46.4 GeV/c2 at 95% CL are obtained, depending on the effecte SU(2) × U(1) invariant couplings assigned to the leptoquark.
Published: 1991

21. Measurement of theZ 0 line shape parameters and the electroweak couplings of charged leptons

Author: M. Jimack, John Allison, D. Axen, A. Jawahery, G. Tysarczyk-Niemeyer, Peter Sherwood, R. W. Springer, B. Holl, N. C. Wood, C. M. Hawkes, M. Cooper, Daniel Lellouch, J. Ludwig, G. J. Van Dalen, K. Runge, P. Bock, A. Simon, Otmar Biebel, D. G. Charlton, Takehiko Mori, I. Zacharov, Horst Breuker, G. A. Snow, C. P. Ward, M. Couch, A. D. Schaile, R. G. Kellogg, C. Y. Chang, P. Taras, Mitsuaki Nozaki, D. A. Hinshaw, R. Humbert, J. T.M. Chrin, Stefano Marcellini, V. H. Winterer, O. Runolfsson, T. Kawamoto, T. J. Smith, S. Orito, S. Bougerolle, P. Mättig, L. Lessard, John H. Schwarz, T. R. Wyatt, Claudio Grandi, S. R. Hou, Gunter Quast, P. Singh, T. Mouthuy, J. M. Lorah, W. Mohr, R. Mir, H. Oh, I. J. Bloodworth, J. G. Layter, S. Sanghera, F. S. Merritt, M. Settles, R. W. L. Jones, G. Beaudoin, M. J. Oreglia, W. J. Collins, G. D. Lafferty, P. Le Du, J. Hart, Y. Yangh, H. Kreutzmann, B. Panzer-Steindel, H. Przysiezniak, A. M. Rossi, K. J. Anderson, A. Astbury, G. Duckeck, D. Karlen, W. R. Gibson, Tohru Takeshita, D. Strom, P. E.L. Clarke, T. Behnke, Paul Kyberd, F. K. Loebinger, G. Giacomelli, T. Tsukamoto, Shlomo Dado, S. Levegrün, G. T. Zorn, T. W. Pritchard, Georges Azuelos, H. M. Bosch, Wolfram Dietrich Zeuner, C. Moisan, J. R. Carter, O. Ganel, P. W. Jeffreys, P. Igo-Kemenes, G. Maringer, G. N. Patrick, K. W. Bell, J. P. Walker, C. Ho, X. C. Lou, Gideon Bella, D. Hochman, N. J. Thackray, H. J. Burckhart, Jacqueline Batley, M. W. Redmond, A. M. Lee, P. G. Murphy, A. J. Martin, Max Weber, H. Jeremie, K. Stephens, A. Rollnik, D. E. Klem, Kiyotomo Kawagoe, R. F. McGowan, J. C. Hill, Giora Mikenberg, J. R. McNutt, B. C. Shen, C. Fukunaga, A. Beck, M. A. Whalley, K. Riles, R. E. Hughes-Jones, U. Maur, R. Van Kooten, E. K. U. Gross, P. Teixeira-Dias, E. Heflin, A. Gaidot, Erez Etzion, M. Kuwano, W. G. Scott, M. Sproston, G. Eckerlin, Gareth J. Barker, R. M. Brown, Lorne Levinson, A. P. Wagner, P. Routenburg, A. Dieckmann, V. Gibson, John Baines, R. Kowalewski, M. J. Losty, M. F. Turner, P. Poffenberger, N. I. Geddes, Shlomit Tarem, P. A. Elcombe, Silvia Arcelli, J. L. Pinfold, A. Buijs, M. H. Lehto, H. O. Ogren, Christoph Geich-Gimbel, J. P. Martin, M. Sasaki, S. De Jong, B. W. Kennedy, D. L. Rees, J. Becker, B. Poli, S. Rossberg, C. J. Oram, D. R. Ward, P. F. Harrison, Stephen Lloyd, J. M. Roney, R. Yaari, S. Bethke, C. K. Hargrove, M. M. Deninno, H. M. Fischer, P. Debu, J. Mildenberger, Harold Nguyen, R. P. Middleton, Marco Cuffiani, J. Kroll, A. Michelini, J. D. Hobbs, F. X. Gentit, N. Wermes, G. G. Hanson, J. E. Conboy, M. Ogg, Ehud Duchovni, R. Shypit, S. A. Robins, D. E. Plane, Stephen Hillier, Michael Dittmar, E.J. Prebys, G. M. Dallavalle, A. Pouladdej, H. Ihssen, B. P. O'Neill, G. Yekutieli, M. S. Dixit, Frans Meijers, Alan Watson, D. J.P. Dumas, J. Hagemann, S. W. Gensler, J. Goldberg, B. Nellen, P. Leblanc, O. Schaile, D. C. Imrie, A. A. Carter, M. J. Goodrick, T. Kobayashi, M. Hansroul, S. W. O'Neale, Peter R Hobson, I. Cohen, S. J. Pawley, Phillip Allport, Claus Kleinwort, L. Köpke, R. J. Homer, S. Wotton, Margret Fincke-Keeler, G. P. Siroli, G. W. Wilson, M. Hauschild, P. S. Wells, D. R. Rust, P. Paschievici, C. J. Virtue, P. Pfister, Gideon Alexander, J. C. Armitage, M. Coupland, Paolo Capiluppi, P. Schenk, P. Lennert, S. Schreiber, M. Weymann, T. J. McMahon, Richard Keeler, C. Wahl, C. P. Howarth, J. E. Pilcher, R. K. Carnegie, H. E. Stier, R. Sobie, N. K. Watson, Claude Leroy, M. W. Moss, J. A. Wilson, J. P. Pansart, P. M. Hattersley, Sachio Komamiya, P. G. Estabrooks, W. Schappert, T. P. Kokott, Rene Brun, J. Banks, P. M. Watkins, S. Weisz, R. D. Heuer, Fabrizio Fabbri, D. Van den plas, I. Wingerter, J. von Krogh, P. Ashton, Dave Robinson, H. Mes, I. P. Duerdoth, L. Janissen, C. Milstene, F. Odorici, Andris Skuja, Tetsuro Mashimo, W. Gorn, G. A. Bahan, M. Jobes, U. Binder, P. Scharff-Hansen, W. J. Larson, J. W. Gary, A. M. Smith, G. Vasseur, B. Lorazo, B. B. Brabson, D. G. Fong, J. Gascon, H. von der Schmitt, Marcello Mannelli, H. Takeda, F. G. Oakham, J. D. Gillies, R. J. Barlow, D. J. Miller, F. Lamarche, R. J. Hemingway, P. Jovanovic, Austin Ball, D. Menszner, and Alessandro Montanari
Subjects: Physics, Particle physics, Muon, Physics and Astronomy (miscellaneous), Electron–positron annihilation, Electroweak interaction, Weinberg angle, Standard Model, Nuclear physics, High Energy Physics::Experiment, Engineering (miscellaneous), Pseudovector, Boson, Lepton
Abstract: We report on an improved measurement of the mass of theZ0 boson, its total width and its partial decay widths into hadrons and leptons, as well as the effective axial vector and vector couplings to charged leptons. These measurements are based on a data set of approximately 160 000 hadronicZ0 decays and 18 000 decays into electrons, muons and taus, recorded by the OPAL experiment at centre of mass energies near the mass of theZ0. The total width and the partial widths to visible final states, derived from the measured cross sections, are used to extract the invisible width. The effective couplings of theZ0 to charged leptons are studied using measurements of the lepton pair cross sections and forward-backward asymmetries at the different centre of mass energy points of theZ0 scan. The implications of our results in the context of the Standard Model are discussed.
Published: 1991

22. A study of - in Z0 decays

Author: Gideon Bella, H. J. Burckhart, Jacqueline Batley, M. Jobes, F. Odorici, R. Mir, U. Binder, H. Oh, H. O. Ogren, Michael Dittmar, C. M. Hawkes, M. Cooper, Daniel Lellouch, F. S. Merritt, G. Yekutieli, R. F. McGowan, Christoph Geich-Gimbel, Silvia Arcelli, M. M. Deninno, Tohru Takeshita, P. Scharff-Hansen, J. Kroll, F. X. Gentit, J. E. Conboy, Paul Kyberd, M. Ogg, R. Shypit, Takehiko Mori, T. Mouthuy, F. K. Loebinger, M. W. Moss, P. Igo-Kemenes, A. Pouladdej, G. Maringer, M. J. Oreglia, H. Jeremie, C. Moisan, J. P. Walker, F. Lamarche, R. E. Hughes-Jones, N. C. Wood, U. Maur, W. J. Larson, J. D. Hobbs, Georges Azuelos, P. M. Hattersley, H. Mes, M. W. Redmond, R. J. Hemingway, I. P. Duerdoth, R. Van Kooten, G. G. Hanson, P. Singh, J. W. Gary, A. Rollnik, K. W. Bell, P. Teixeira-Dias, G. A. Snow, C. P. Ward, A. A. Carter, G. Giacomelli, Max Weber, P. E.L. Clarke, M. Sprotson, J. R. Carter, A. M. Rossi, K. J. Anderson, Misao Sasaki, T. Behnke, R. W. L. Jones, M. H. Lehto, L. Janissen, B. C. Shen, P. Jovanovic, A. M. Smith, G. N. Patrick, E.J. Prebys, Austin Ball, Kiyotomo Kawagoe, T. Tsukamoto, D. E. Klem, S. Levegrün, D. Menszner, R. Sobie, G. Vasseur, B. Lorazo, S. Wotton, P. Le Du, W. G. Scott, M. S. Dixit, Frans Meijers, G. Beaudoin, M. Jimack, John Allison, H. Kreutzmann, B. Panzer-Steindel, D. Hochman, N. J. Thackray, I. J. Bloodworth, A. Simon, Otmar Biebel, E. K. U. Gross, A. P. Wagner, Alessandro Montanari, Gunter Quast, M. Weymann, K. Stephens, J. M. Roney, N. I. Geddes, R. Yaari, D. G. Charlton, J. R. McNutt, A. Gaidot, M. Couch, M. F. Turner, M. Kuwano, R. Kowalewski, M. Geerts, J. P. Martin, S. Bethke, B. B. Brabson, Shlomo Dado, C. Fukunaga, R. Humbert, Marco Cuffiani, M. Settles, H. E. Stier, John Hill, B. Poli, D. G. Fong, J. Gascon, X. C. Lou, S. De Jong, H. von der Schmitt, S. Schreiber, J. T.M. Chrin, M. J. Losty, G. Duckeck, T. J. McMahon, J. D. Gillies, P. G. Estabrooks, R. G. Kellogg, P. Routenburg, P. G. Murphy, D. Strom, V. Gibson, B. P. O'Neill, J. Hart, H. M. Fischer, T. Kawamoto, A. Michelini, Giora Mikenberg, G. T. Zorn, John Baines, R. J. Barlow, A. Astbury, P. M. Watkins, P. Debu, G. W. Wilson, Marcello Mannelli, R. K. Carnegie, Stefano Marcellini, A. Dieckmann, S. Orito, John H. Schwarz, J. Hagemann, D. Karlen, J. A. Wilson, D. C. Imrie, Y. Yang, C. Y. Chang, M. Fincke-Keeler, H. M. Bosch, Wolfram Dietrich Zeuner, Andris Skuja, S. A. Robins, I. Wingerter, J. L. Pinfold, O. Ganel, Tetsuro Mashimo, J. G. Layter, P. Taras, A. J. Martin, D. R. Ward, C. J. Oram, P. F. Harrison, Mitsuaki Nozaki, K. Riles, G. P. Siroli, W. Schappert, W. Gorn, J. Mildenberger, S. Bougerolle, G. A. Bahan, W. J. Collins, Harold Nguyen, S. Sanghera, Stephen Lloyd, J. M. Lorah, Erez Etzion, D. E. Plane, G. D. Lafferty, Gareth J. Barker, C. K. Hargrove, B. Holl, D. A. Hinshaw, Shlomit Tarem, W. Mohr, P. Pfister, Stephen Hillier, G. M. Dallavalle, G. Eckerlin, T. J. Smith, Phillip Allport, P. A. Elcombe, S. Rossberg, T. W. Pritchard, H. Takeda, I. Zacharov, J. C. Armitage, R. P. Middleton, F. G. Oakham, Alan Watson, D. L. Rees, D. J.P. Dumas, J. Becker, P. Mättig, S. J. Pawley, Horst Breuker, G. J. VanDalen, B. Nellen, P. Leblanc, M. Hansroul, W. R. Gibson, C. Ho, Claus Kleinwort, L. Köpke, R. J. Homer, D. Axen, P. Schenk, A. D. Schaile, A. Beck, A. Jawahery, Gideon Alexander, Paolo Capiluppi, G. Tysarczyk-Niemeyer, E. Heflin, M. J. Goodrick, I. Cohen, R. M. Brown, Lorne Levinson, N. Wermes, B. W. Kennedy, Ehud Duchovni, D. R. Rust, H. Ihssen, S. W. Gensler, T. Kobayashi, P. Lennert, J. Banks, S. Weisz, R. D. Heuer, Fabrizio Fabbri, D. Van den plas, J. von Krogh, Peter Sherwood, R. W. Springer, J. Ludwig, K. Runge, P. Bock, P. Ashton, Dave Robinson, Sachio Komamiya, V. H. Winterer, S. R. Hou, T. P. Kokott, Rene Brun, N. K. Watson, S. W. O'Neale, Peter R Hobson, M. Hauschild, P. Paschievici, P R Poffenberger, D. J. Miller, H. Przysiezniak, O. Runolfsson, C. Wahl, L. Lessard, Claudio Grandi, P. W. Jeffreys, P. S. Wells, A. M. Lee, C. J. Virtue, C. P. Howarth, Terry Richard Wyatt, J. E. Pilcher, M. Coupland, O. Schaile, M. A. Whalley, A. Buijs, Richard Keeler, Claude Leroy, J. P. Pansart, and C. Milstene
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Meson, Branching fraction, High Energy Physics::Lattice, Electron–positron annihilation, Nuclear Theory, High Energy Physics::Phenomenology, Hadron, Elementary particle, Nuclear physics, Pair production, Pion, High Energy Physics::Experiment, Nuclear Experiment
Abstract: In this paper an investigation of the production of D ∗ ± mesons produced in e + e − collisions at energies around the Z 0 pole is presented. Based on 115 D ∗ ± mesons with x D∗  2E D ∗ /E cm > 0.2 the properties of D ∗ mesons produced in the reaction Z 0 → c c are studied. Fixing the yield and the fragmentation function of bottom quarks to the values obtained at LEP using lepton tags, and average energy fraction of the D ∗ ± mesons from primary charmed quarks of 〈x c → D ∗ 〉 = 0.52 ± 0.03 +- 0.01 is found and Γ z 0 →c c = (323 ± 61 ± 35) MeV is determined. The first error is the combined statistical and systematic error from this experiment, and the second the total error from other sources.
Published: 1991

23. A measurement of energy correlations and a determination of αs(M2Z) e+e- annihilations at √s=91 GeV

Author: F. X. Gentit, F. Odorici, H. Takeda, G. A. Snow, C. P. Ward, C. Y. Chang, M. S. Dixit, G. Mikenberg, G.W. Wilson, L. Janissen, R. Stroehmer, W. J. Collins, M. T. French, Mitsuaki Nozaki, Christoph Geich-Gimbel, P. Singh, Erez Etzion, B. J. Saunders, Gareth J. Barker, D. C. Imrie, T. W. Pritchard, P. Igo-Kemenes, S. Rossberg, Michael Dittmar, M. M. Deninno, M. J. Losty, R. W. L. Jones, R. P. Middleton, J. Kroll, G. Yekutieli, G. Maringer, T. Mashino, J. Goldberg, H. Jeremie, B. Nellen, Shlomo Dado, S. L. Lloyd, G. P. Siroli, P. Leblanc, P. Le Du, H. Kreutzmann, R. G. Kellogg, J. E. Conboy, R. E. Hughes-Jones, U. Maur, A. A. Carter, A. Jawahery, J.P. Pansart, N. K. Watson, P. G. Murphy, J. Grunhaus, M. Ogg, J. D. Gillies, M. J. Goodrick, Stefano Marcellini, T. J. Smith, H. Oh, I. Cohen, G. Tysarczyk-Niemeyer, D. G. Fong, V. Gibson, Kiyotomo Kawagoe, K. J. Anderson, A. Pouladdej, Peter Sherwood, Gideon Bella, J. Gascon, S. Wotton, N. C. Wood, H. J. Burckhart, P. Mättig, B. C. Shen, B. Wuensch, A. M. Rossi, J. M. Lorah, M. Weymann, G. D. Lafferty, Takashi Yoshida, R. W. Springer, A. P. Wagner, J. M. Roney, H. von der Schmitt, C. Fukunaga, D. E. Klem, G.T.J. Arnison, D. J. Miller, A. Buijs, J. Ludwig, K. Runge, P. Bock, Jacqueline Batley, A. A. Macbeth, M. Hauschild, Makoto Minowa, W. Mohr, I. J. Bloodworth, T. Tsukamoto, H. E. Stier, G. Knop, J. Mildenberger, Harold Nguyen, J. Hagemann, M. F. Turner, P. G. Estabrooks, S. Schreiber, T. J. McMahon, R. K. Carnegie, N. I. Geddes, M. Jimack, D. Karlen, O. Ganel, A. J. Martin, F. Lamarche, P. Lennert, Marcello Mannelli, T. P. Kokott, Rene Brun, C. N. P. Gee, J. A. Wilson, B. Poli, F. S. Merritt, C. M. Hawkes, J. Allison, Daniel Lellouch, P. M. Watkins, M. Jobes, U. Binder, W. J. Murray, R. J. Hemingway, R. Kowalewski, H. M. Fischer, D. Granite, Takehiko Mori, J. Ma, W. Schappert, D. Strom, P. Scharff-Hansen, Paul Kyberd, F. K. Loebinger, G. T. Zorn, P. Jovanovic, A. Michelini, I. Wingerter, W. J. Larson, J. D. Hobbs, M. Sasaki, E. K. U. Gross, A. Gaidot, P. E.L. Clarke, M. Kuwano, T. Behnke, Austin Ball, D. Menszner, M. W. Redmond, Wolfram Dietrich Zeuner, K. Riles, J. L. Pinfold, J. W. Gary, S. A. Robins, M. Sproston, A. Rollnik, M. W. Moss, M. Z. Akrawy, I. Harrus, A. M. Smith, P. M. Hattersley, M. J. Oreglia, M. H. Lehto, P. Routenburg, J. R. Carter, Alessandro Montanari, A. Dieckmann, H. Mes, G. Vasseur, J. von Krogh, J. Raab, B. Lorazo, F. G. Oakham, Andris Skuja, P. A. Elcombe, P. Ashton, B. Holl, S. W. O'Neale, Peter R Hobson, H. El Mamouni, Tohru Takeshita, R. Yaari, S. Bethke, Marco Cuffiani, D. L. Rees, A. Shapira, J. Becker, A. D. Schaile, I. P. Duerdoth, Georges Azuelos, S. J. Pawley, Claus Kleinwort, L. Köpke, Horst Breuker, G. N. Patrick, A. Simon, Otmar Biebel, K. W. Bell, Max Weber, O. Schaile, W. Gorn, P. S. Wells, J. C. Hill, G. Giacomelli, C. J. Virtue, Terry Richard Wyatt, D. G. Charlton, A. T. Watson, M. Coupland, E.J. Prebys, J. Banks, Gunter Quast, M. Couch, S. Weisz, R. D. Heuer, Fabrizio Fabbri, D. Van den plas, R. Humbert, Frans Meijers, J. T.M. Chrin, T. Kawamoto, V. H. Winterer, S. Orito, John H. Schwarz, S. R. Hou, J. G. Layter, C. Wahl, C. P. Howarth, J. E. Pilcher, N. Wermes, C. K. Hargrove, Ehud Duchovni, R. A. Sansum, H. Ihssen, S. Sanghera, S. W. Gensler, Phillip Allport, J. P. Martin, C. M. Roach, B.P. O'Neil, D. E. Plane, Stephen Hillier, G. M. Dallavalle, P. Farthouat, Gideon Alexander, Paolo Capiluppi, D. Hochman, N. J. Thackray, J. Hart, G. J. VanDalen, R. J. Barlow, P. Pfister, Y. Yang, D. J.P. Dumas, P. W. Jeffreys, J. C. Armitage, T. Kobayashi, A. M. Lee, K. Stephens, J. R. McNutt, P. Debu, M. Hansroul, R. J. Homer, John Baines, M. Regimbald, O. Runolfsson, A. J.P. O'Dowd, J. P. Walker, D. R. Ward, W. R. Gibson, C. Ho, A. Beck, E. Heflin, R. M. Brown, Lorne Levinson, L. Lessard, B. W. Kennedy, C. Milstene, and H. Hagedorn
Subjects: Coupling constant, Quantum chromodynamics, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Electron–positron annihilation, Hadron, Nuclear physics, Renormalization, Particle decay, High Energy Physics::Experiment, Astrophysics::Earth and Planetary Astrophysics, Boson
Abstract: From an analysis of multi-hadron events from Z 0 decays, values of the strong coupling constant α s ( M 2 Z 0 )=0.131±0.006 (exp)±0.002(theor.) and α s ( M z 0 2 ) = −0.009 +0.007 (exp.) −0.002 +0.006 (theor.) are derived from the energy-energy correlation distribution and its asymmetry, respectively, assuming the QCD renormalization scale μ = M Z 0 . The theoretical error accounts for differences between O ( α 2 s ) calculations. A two parameter fit Λ MS and the renormalization scale μ leads to Λ MS =216±85 MeV and μ 2 s =0.027±0.013 or to α s ( M 2 Z 0 )=0.117 +0.006 −0.008 (exp.) for the energy-energy correlation distribution. The energy-energy correlation asymmetry distribution is insensitive to a scale change: thus the α s value quoted above for this variable includes the theoretical uncertainty associated with the renormalization scale.
Published: 1990

24. The Heidelberg cosmic ray project - aims and status

Author: C. Gamp, B. Stadler, S. Polenz, J. Heintze, Werner Hofmann, Bernhard Schmidt, J. Spitzer, Bogdan Povh, C. Wiedner, and P. Lennert
Subjects: Physics, Nuclear and High Energy Physics, Range (particle radiation), Muon, Air shower, Astronomy, Cosmic ray, Astrophysics, Atomic and Molecular Physics, and Optics
Abstract: A new type of Extensive Air Shower (EAS) array is proposed which is based on the measurement of individual cosmic ray tracks and muon identification. Air showers can be detected in the range from 10 12 eV up to the highest energies. The direction of the primary γ-ray will be reconstructed with accuracies typically in the range of 0.1° to 0.3°. The sensitivity for the detection of point sources will be improved by about a factor of 100 in comparison to existing conventional EAS arrays or Atmospheric Cerenkov Telescopes.
Published: 1990

25. Measurements of the decay of the Z0 into lepton pairs

Author: J. Waterhouse, B. J. Saunders, Phillip Allport, B. C. Shen, H. M. Fischer, T. J. McMahon, J. C. Armitage, E. J. Spreadbury, D. Duchesneau, J. A. Wilson, P. Grosse-Wiesmann, A. J.P. O'Dowd, I. Cohen, P. Le Du, D. Granite, C. Milstene, R. W.L. Jones, D. G. Fong, E. Jin, H. von der Schmitt, D. J.P. Dumas, S. R. Hou, Gideon Bella, J. von Krogh, J. Raab, G. A. Snow, C. P. Ward, G. Knop, Despina Hatzifotiadou, H. J. Burckhart, H. Jeremie, H. Kreutzmann, Jacqueline Batley, C. Geich-Gimbel, P. Ashton, R. M. Brown, G. T.J. Arnison, Marcello Mannelli, H. Wang, Andris Skuja, F. S. Merritt, G. D. Lafferty, Michael Dittmar, Kiyotomo Kawagoe, Tetsuro Mashimo, J. L. Pinfold, Gunter Quast, C. J. Virtue, J. P. Martin, F. Roehner, P. Kyberd, Paolo Capiluppi, J. M. Roney, Tohru Takeshita, K. W. Bell, P. Bock, D. G. Charlton, M. Couch, A. M. Rossi, D. E. Plane, W. Gorn, P. A. Elcombe, G. Yekutieli, W. R. Gibson, T. P. Kokott, B. Holl, Stephen Hillier, J. Heintze, P. G. Estabrooks, M. Jobes, D. Hochman, I. P. Duerdoth, D. L. Rees, P. Routenburg, R. Kowalewski, S. Schreiber, J. T.M. Chrin, C. K. Hargrove, C. M. Roach, B. P. O'Neill, D. Karlen, N. Lupu, A. Dieckmann, C. Fukunaga, P. Scharff-Hansen, W. J. Larson, A. Buijs, G. J. VanDalen, H. Boerner, G. P. Siroli, A. Jawahery, Peter Sherwood, T. Kawamoto, M. Jimack, R. W. Springer, M. Coupland, N. K. Watson, P. G. Murphy, U. Maur, C. N.P. Gee, A. M. Smith, H. El Mamouni, D. Strom, Horst Breuker, G. T. Zorn, P. M. Watkins, P. Igo-Kemenes, Wolfram Dietrich Zeuner, F. Beck, R. Ströhmer, A. Wagner, Rolf-Dieter Heuer, T. Tsukamoto, G. N. Patrick, B. Poli, M. Sproston, A. Rollnik, S. Orito, S. Zylberajch, S. Sanghera, C. Wahl, M. F. Turner, H. Oh, O. Runolfsson, P. Lennert, J. M. Lorah, H. Yamashita, B. Lorazo, M. Z. Akrawy, Makoto Minowa, H. E. Stier, T. W. Pritchard, M. Weymann, M. W. Moss, W. Mohr, M. M.B. Lasota, P. S. Hinde, M. Regimbald, P. M. Hattersley, A. Possoz, H. Takeda, I. Wingerter, C. Beard, C. Ho, Marco Cuffiani, J. W. Gary, E. Heflin, S. Bethke, B. W. Kennedy, J. C. Hill, Misao Sasaki, M. J. Oreglia, N. I. Geddes, G. J. Barker, N. C. Wood, M. M. Deninno, R. J. Barlow, A. A. Carter, D. J. Miller, J. Schwarz, J. Kroll, M. Ogg, J. R. Carter, R. Yaari, J. Ma, W. J. Murray, L. Levinson, P. Jovanovic, S. Wotton, Austin Ball, F. K. Loebinger, F. X. Gentit, J. E. Conboy, A. C. McPherson, W. Schappert, M. S. Dixit, Alessandro Montanari, B. Nellen, J. Banks, G. Azuelos, H. Mes, A. Simon, S. W. Gensler, R. E. Hughes-Jones, A. Shapira, Aldo Michelini, E. Gross, Fabrizio Fabbri, D. Van den plas, G. Tysarczyk, O. Ganel, K. Riles, M. W. Redmond, S. Weisz, P. Farthouat, A. Pouladdej, G. Mikenberg, T. Kobayashi, R. K. Carnegie, O. Schaile, D. C. Imrie, J. Ludwig, C. P. Howarth, J. Grunhaus, Terry Richard Wyatt, F. G. Oakham, J. E. Pilcher, E. Duchovni, M. Hansroul, A. A. Macbeth, G. W. Wilson, P. W. Jeffreys, S. J. Pawley, G. Maringer, Claus Kleinwort, L. Köpke, Masatoshi Koshiba, J. Hart, M. Hauschild, D. E. Klem, Harold Nguyen, V. H. Winterer, P. Leblanc, R. J. Homer, L. Lessard, K. J. Anderson, Y. Yang, Achim Müller, O. Biebel, John Allison, C. Y. Chang, A. D. Schaile, Stephen Lloyd, R. G. Kellogg, B. Gandois, Mitsuaki Nozaki, M. Weber, Stefano Marcellini, K. Stephens, Masatoshi Imori, John Baines, G. Bavaria, F. Odorici, D. R. Ward, F. Lamarche, M. T. French, O. W. Davies, M. J. Losty, Richard J Hemingway, S. W. O'Neale, Peter R Hobson, A. T. Watson, Rene Brun, J. Hagemann, I. J. Bloodworth, James D Gillies, A. Perez, R. A. Sansum, G. M. Dallavalle, J. Goldberg, T. J. Smith, P. Mättig, C. M. Hawkes, Daniel Lellouch, Takehiko Mori, R. P. Middleton, D. Menszner, M. J. Goodrick, J. G. Layter, J. D. Hobbs, G. Alexander, G. Giacomelli, S. Dado, H. Hagedorn, Frans Meijers, K. Runge, B. Wuensch, and N. Wermes
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Standard Model (mathematical formulation), Basis (linear algebra), Electron–positron annihilation, Hadron, Particle Physics - Experiment, Lepton
Abstract: We report on a measurement of the processes e+e−→e+e−, e+e−→μ+μ−, and e+e−→τ+τ− near the Z0 pole. On the basis of 163 e+e−, 101 μ+μ− and 87 τ+τ− events we obtain Γee=89±4±4 MeV, Γμμ=85±9±6 MeV and Γττ=87±10±8 MeV, compatible with the standard model. Combining these with our previous results on hadronic Z0 decays, we find a hadronic width Γhad=1787±81±90 MeV and an invisible width Γinv=552±85±71 MeV.
Published: 1990

26. Cosmic ray tracking — a new approach to high-energy γ-astronomy

Author: M. Feuerstack, J. Heintze, P. Lennert, B. Müller, S. Polenz, B. Schmidt, J. Spitzer, B. Stadler, S. Gamp, W. Hofmann, T. Kihm, J. Knöppler, M. Panter, B. Povh, and C. Wiedner
Subjects: Physics, Range (particle radiation), Nuclear and High Energy Physics, Muon, Air shower, Point source, Astronomy, Angular resolution, Cosmic ray, Sensitivity (control systems), Tracking (particle physics), Instrumentation
Abstract: A new type of Extensive Air Shower (EAS) array is proposed which is based on the measurement of individual cosmic ray tracks and muon identification. Air showers can be detected in the range from 1012 eV up to the highest energies. The direction of the primary γ-ray will be reconstructed with accuracies typically in the range of 0.1° to 0.3°. The sensitivity for the detection of point sources will be improved by about a factor of 100 in comparison to existing conventional EAS arrays or Atmospheric Cerenkov Telescopes.
Published: 1992

27. The recent performance of the Omega RICH detector in experiment WA89 at CERN

Author: W. Klempt, M. Boss, K. Martens, G. Wälder, O. Thilmann, H. W. Siebert, U. Müller, W. Beusch, H. Rieseberg, Vincent J Smith, S.G. Gerassimov, Jürgen Engelfried, P. Lennert, and Dave M Newbold
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Physics::Instrumentation and Detectors, Detector, Hyperon, Omega, Particle identification, Particle detector, Nuclear physics, Antiproton, Antimatter, Physics::Accelerator Physics, High Energy Physics::Experiment, Detectors and Experimental Techniques, Nuclear Experiment, Instrumentation, Cherenkov radiation
Abstract: The hyperon beam experiment WA89 at CERN uses the upgraded Omega RICH detector for identification of π, K and p/p from Σ − -N reactions. Cherenkov photons from a 5 m long nitrogen radiator are detected in drift chambers with TMAE-loaded ethane. Recent results on the performance of the detector are presented.
Published: 1995

28. Measurement of the polarization of $$\Lambda ^0 , \overline \Lambda ^0 , \Sigma ^ + $$ and ?? produced in a ?? beam of 330 GeV/c

Author: F. Charignon, E. Albertson, L. Schmitt, Charles Ray Newsom, E. A. Chudakov, Jürgen Engelfried, R. Touillon, H. Rudolph, K. Rohrich, S. Paul, F. Dropmann, M. Dameri, C. Scheel, S. Ljungfelt, H. W. Siebert, R. Michaels, S. G. Gerassimov, M. I. Adamovich, A. Simon, K.H. Brenzinger, M. Godbersen, Ph Martin, H.M. Lauber, U. Müller, P. Grafström, B. Osculati, W. Brückner, C. Bérat, K. Martens, B. Volkemer, Dario Barberis, A. Trombini, J.Y. Hostachy, J. Chauvin, F. Faller, W. Beusch, P. Lennert, Bogdan Povh, G. Rosner, Th. Kallakowsky, Mikhail Zavertyaev, S. Kluth, S. Brons, H. Rieseberg, Leonardo Paolo Rossi, B.R. French, A. Wenzel, R.B. Hurst, Th. Walcher, G. Walder, A. Brunengo, M. Buénerd, M. Rey-Campagnolle, and Yu. A. Alexandrov
Subjects: Physics, Nuclear and High Energy Physics, Large Hadron Collider, High Energy Physics::Phenomenology, Nuclear Theory, Hyperon, Lambda, Polarization (waves), Omega, Nuclear physics, Baryon, Nuclear fusion, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, Beam (structure), Particle Physics - Experiment
Abstract: The polarization of Lambda0 , AntiLambda0 , Sigma+ and Xi- inclusively produced in Sigma- induced interactions at 330 GeV has been measured in the experiment WA89 at CERN. This is the first measurement of polarization of baryons produced by a hyperon beam. No polarization of AntiLambda is observed, as was also the case in proton beam data. At transverse momenta of about 1~GeV/c Lambda0 and Sigma+ show little polarization, significantly lower than in the proton beam data, while Xi- have a polarization comparable to the polarization of Lambda0 produced in proton beams. The polarization of Lambda0, AntiLambda0, Sigma+ and Xi- inclusively produced in Sigma- induced interactions at 330 GeV has been measured in the experiment WA89 at CERN. This is the first measurement of polarization of baryons produced by a hyperon beam. No polarization of AntiLambda is observed, as was also the case in proton beam data. At transverse momenta of about 1GeV/c Lambda0 and Sigma+ show little polarization, significantly lower than in the proton beam data, while Xi- have a polarization comparable to the polarization of Lambda0 produced in proton beams. The polarization of Lambda0, AntiLambda0, Sigma+ and Xi- inclusively produced in Sigma- induced interactions at 330 GeV has been measured in the experiment WA89 at CERN. This is the first measurement of polarization of baryons produced by a hyperon beam. No polarization of AntiLambda is observed, as was also the case in proton beam data. At transverse momenta of about 1GeV/c Lambda0 and Sigma+ show little polarization, significantly lower than in the proton beam data, while Xi- have a polarization comparable to the polarization of Lambda0 produced in proton beams. The polarization of Lambda0, AntiLambda0, Sigma+ and Xi- inclusively produced in Sigma- induced interactions at 330 GeV has been measured in the experiment WA89 at CERN. This is the first measurement of polarization of baryons produced by a hyperon beam. No polarization of AntiLambda is observed, as was also the case in proton beam data. At transverse momenta of about 1GeV/c Lambda0 and Sigma+ show little polarization, significantly lower than in the proton beam data, while Xi- have a polarization comparable to the polarization of Lambda0 produced in proton beams.
Published: 1995

29. Signal propagation in long wire chambers

Author: M Zimmer, P. Bock, Jürgen Engelfried, Joachim Heintze, M Russ, P. Lennert, and T Friedrich
Subjects: Physics, Jet (fluid), Wire chamber, business.industry, Proportional counter, Electrical termination, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Tracking (particle physics), Signal, GeneralLiterature_MISCELLANEOUS, Radio propagation, Optics, Spark chamber, business, Instrumentation, Mathematical Physics
Abstract: The propagation of signals in long proportional counters or multi-wire tracking chambers is simulated, using numerical solutions of the multi-wire telegraph equations. The results are compared to experimental data, recorded with a proportional counter and a multi-wire test chamber. The signal shape, the charge division ratio and, in the case of the drift chamber, also the cross talk between the wires, are well reproduced. Similar shapes for signals and their cross talk can be obtained with a properly chosen electrical termination. It is shown how data from a multi-wire chamber can then be corrected for cross talk. The effects limiting the precision of position measurements along the wires with the charge division method are discussed. The simulation was applied to the reconstruction of tracks measured with the OPAL JET chamber.
Published: 2012

30. The Omega-RICH

Author: G. Wälder, Jürgen Engelfried, W. Beusch, H. W. Siebert, H. Rieseberg, S.G. Gerassimov, P. Lennert, F. Faller, U. Müller, R. Michaels, and K. Martens
Subjects: Physics, Nuclear and High Energy Physics, Photon, Spectrometer, business.industry, Hyperon, Omega, Particle identification, Optics, Detectors and Experimental Techniques, business, Instrumentation, Image resolution, Quartz, Beam (structure)
Abstract: A large-aperture RICH for identification of secondary particles is in operation at the Omega spectrometer since 1984. Photons are detected in drift chambers with quartz windows, using TMAE-loaded counting gases. The RICH was used by two experiments, WA69 and WA82, until 1988. It was then equipped with new drift chambers and mirrors and is in use since 1990 mainly for the hyperon beam experiment WA89. The present setup is described in more detail, and efficiencies, resolutions and particle separation achieved are discussed.
Published: 1994

31. Measurement of the angular distributions of particles in air showers

Author: M. Panter, J. Heintze, M. Rosales, H. Wirth, R. Zink, C. A. Wiedner, R. Reimers, S. Polenz, V. Matheis, D. Brecht, Thomas Kihm, S. Gamp, P. Lennert, Werner Hofmann, and J. Knöppler
Subjects: Nuclear physics, Core (optical fiber), Physics, Shower, Air shower, Physics::Instrumentation and Detectors, Position (vector), Astrophysics::High Energy Astrophysical Phenomena, Monte Carlo method, Astrophysics::Instrumentation and Methods for Astrophysics, High Energy Physics::Experiment, Scintillator, Charged particle
Abstract: Using a scintillator air shower array to determine the direction, size, and core position of extensive air showers and a large-volume drift chamber to track individual shower particles, we have measured the angular distributions of charged particles in extensive air showers at sea level. The distributions are sharply peaked around the shower axis, with characteristic widths of a few degrees. Particles at large distances from the shower axis tend to point towards the axis as their origin. Monte Carlo models of air showers reproduce the measured distributions rather well
Published: 1992

32. Evidence for the existence of the strange b-flavoured meson $B^{0}_{s}$ in $Z^{0}$ decays

Author: Margret Fincke-Keeler, D. Axen, A. Jawahery, G. Tysarczyk-Niemeyer, J. P. Martin, F. S. Merritt, J. Goldberg, K. Stephens, Peter Sherwood, J. R. McNutt, J. C. Clayton, S. De Jong, B. Nellen, V. Gibson, G. Quast, John Baines, R. Van Kooten, D. Pitman, M. H. Lehto, D. R. Ward, G. Transtromer, R. W. Springer, Alexander Wagner, J. Hagemann, J. Ludwig, F. C. Grant, M. A. Whalley, P. Leblanc, K. Runge, P. Bock, P. Pfister, P. F. Harrison, H. G. Evans, T. G. Shears, J. A. McKenna, P. D. Acton, Stephen Lloyd, P. G. Estabrooks, R. K. Keeler, M. J. Goodrick, I. Cohen, A. Buijs, A. Yeaman, M. Tecchio, R. F. McGowan, I. J. Bloodworth, Kiyotomo Kawagoe, N. Paz-Jaoshvili, W. R. Gibson, A. D. Schaile, Tohru Takeshita, Gideon Bella, H. J. Burckhart, Erez Etzion, F. Lamarche, Phillip Allport, Stefan Kluth, Jacqueline Batley, N. K. Watson, P. M. Watkins, P. Berlich, Shlomit Tarem, J. M. Roney, M. Settles, S. Barnett, A. Simon, Otmar Biebel, L. Köpke, H. Mes, D. Hochman, N. J. Thackray, A. Beck, V. H. Winterer, D. Strom, I. P. Duerdoth, E. Heflin, G. E. Richards, D. G. Charlton, D. L. Wagner, S. Rossberg, C. J. Oram, Georges Azuelos, M. Foucher, C. Moisan, J. P. Walker, H. O. Ogren, Christoph Geich-Gimbel, P. Weber, R. P. Middleton, R. J. Hemingway, H. Deng, R. Humbert, R. M. Brown, P. Teixeira-Dias, D. R. Rust, Lorne Levinson, J. F. Kral, K. W. Bell, Gideon Alexander, Paolo Capiluppi, P. Schenk, P. Lennert, J. Kroll, P. Poffenberger, Silvia Arcelli, B. W. Kennedy, F. X. Gentit, Max Weber, A. Gaidot, Claude Leroy, J. P. Pansart, G. W. Wilson, D. Karlen, C. Burgard, P. Jovanovic, M. Kuwano, J. E. Conboy, T. Wlodek, D. G. Fong, P. Singh, J. C. Hill, Misao Sasaki, W. J. Collins, M. Sproston, T. Kawamoto, J. Gascon, H. von der Schmitt, A. Pouladdej, B. C. Shen, Austin Ball, D. Menszner, Randall Sobie, G. D. Lafferty, R. W. L. Jones, S. Orito, M. Rosvick, D. E. Plane, R. Mir, Sachio Komamiya, P. Routenburg, A. K. Honma, Alessandro Montanari, W. G. Scott, Stephen Hillier, P. Le Du, T. W. Pritchard, E. Ros, A. T. Watson, J. W. Gary, J. Hart, N. Tesch, A. Dieckmann, B. Panzer-Steindel, G. M. Dallavalle, R. Kowalewski, Marcello Mannelli, J. E. Duboscq, M. J. Oreglia, P. Igo-Kemenes, G. Maringer, M. Hauschild, A. Astbury, M. Jobes, H. Jeremie, J. D. Gillies, R. E. Hughes-Jones, U. Maur, U. Binder, P. A. Elcombe, C. Markus, J. Banks, M. Hansroul, E. do Couto e Silva, P. Scharff-Hansen, M. J. Losty, P. Paschievici, J. R. Carter, T. P. Kokott, Carla Sbarra, G. N. Patrick, O. Ganel, N. J. Tresilian, S. Wotton, R. J. Barlow, A. J. Martin, S. Weisz, C. H. Shepherd-Themistocleous, G. Beaudoin, D. J.P. Dumas, R. D. Heuer, R. J. Homer, C. M. Hawkes, M. Cooper, Fabrizio Fabbri, John Hobbs, Daniel Lellouch, Shlomo Dado, A. M. Smith, P. E.L. Clarke, J. Steuerer, D. Van den plas, D. A. Hinshaw, G. Vasseur, X. C. Lou, M. F. Turner, Takehiko Mori, B. Lorazo, G. G. Hanson, D. L. Rees, R. Yaari, S. Bethke, Marco Cuffiani, J. Becker, C. Jui, G. Giacomelli, C. Wahl, C. K. Hargrove, G. J. VanDalen, J. von Krogh, D. C. Imrie, E.J. Prebys, C. P. Howarth, T. Behnke, N. Wermes, J. E. Pilcher, G. P. Siroli, M. S. Dixit, Ehud Duchovni, R. Shypit, Frans Meijers, H. Ihssen, C. Y. Chang, Christoph Schwick, Dave Robinson, P. Taras, Mitsuaki Nozaki, S. W. Gensler, M. Morii, S. W. O'Neale, Peter R Hobson, L. A. del Pozo, Andris Skuja, J. M. Lorah, Tetsuro Mashimo, J. G. Layter, W. Gorn, W. Mohr, T. J. Smith, G. A. Bahan, Michael Dittmar, Horst Breuker, P. M. Hattersley, G. Yekutieli, P. Mättig, D. J. Miller, F. G. Oakham, A. A. Carter, F. Odorici, O. Schaile, M. Yurko, P. S. Wells, G. Duckeck, P. W. Jeffreys, R. Ströhmer, A. M. Lee, Terry Richard Wyatt, G. T. Zorn, M. Coupland, H. M. Bosch, Wolfram Dietrich Zeuner, S. Schreiber, T. J. McMahon, J. Schwiening, R. K. Carnegie, J. A. Wilson, W. Schappert, Paul Kyberd, F. K. Loebinger, M. W. Redmond, H. Przysiezniak, A. Rollnik, N. I. Geddes, T. Kobayashi, C. J. Virtue, B. Boden, B. Poli, J. Mildenberger, Harold Nguyen, H. M. Fischer, A. Michelini, A. C. Janissen, T. Hilse, O. Runolfsson, M. Jimack, John Allison, T. Mouthuy, Claudio Grandi, S. Bougerolle, Giora Mikenberg, R. G. Kellogg, A. M. Rossi, T. Tsukamoto, S. Levegrün, Stefano Marcellini, James Letts, G. A. Snow, C. P. Ward, and K. J. Anderson
Subjects: Quark, Semileptonic decay, Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Meson, Branching fraction, Electron–positron annihilation, Hadron, Particle Physics - Experiment, Conjugate
Abstract: We present evidence for the existence of the strange b-flavoured meson Bs0 in a data sample of 470 628 hadronic Z0 decays recorded with the OPAL detector at LEP. A signal of 18.3±5.2 (stat.)±0.9(syst.) D s − l + pairs (or charge conjugate, l = e or l = μ ) is found after background subtraction, where the Ds meson is detected in the oπ and K∗0 K final states. Interpreting this signal as coming from the semileptonic decay B s 0 → D s − l + v X and combining t he two decay modes of the Ds, we find f ( b →B s 0 )B( B s 0 → D s − l + v X )B D s − →φ π − ) = [3.9±1.1 ( stat. )±0.8( syst. )]×10 −4 , where f ( b →B s 0 ) is the fraction of b quarks that results in a B0s meson in Z0 decays. This signal for the Bs0 is supported by our observation of an excess of 147 ± 48 inclusive Ds mesons in the φπ and K∗0K modes above the number expected from B0 and B+ decays and from the fragmentation of primary c quarks. In addition, a search is made for the exclusive decay Bs0→J/ψφ. Based on one candidate event the 90% confidence level upper limit is determined to be f ( b → B s 0 ) B ( B s 0 → J /ψφ) .
Published: 1992

33. A measurement of the forward-backward charge asymmetry in hadronic decays of the $Z^{0}$

Author: W. J. Collins, Randall Sobie, G. D. Lafferty, P. Singh, D. Axen, A. Jawahery, Silvia Arcelli, R. W. L. Jones, T. W. Pritchard, G. Tysarczyk-Niemeyer, P. Le Du, Peter Sherwood, R. Van Kooten, D. Pitman, B. Panzer-Steindel, C. Moisan, J. P. Walker, R. W. Springer, Alexander Wagner, M. H. Lehto, J. Goldberg, P. Teixeira-Dias, J. Hagemann, J. Ludwig, K. Runge, P. Bock, Paul Kyberd, F. K. Loebinger, B. Nellen, P. Leblanc, M. F. Turner, Kiyotomo Kawagoe, P. Poffenberger, M. W. Redmond, A. Rollnik, R. Mir, H. Przysiezniak, J. M. Roney, Tara Shears, J. P. Martin, John Hill, S. De Jong, Sachio Komamiya, P. Berlich, H. G. Evans, P. Weber, L. Köpke, Gideon Bella, H. J. Burckhart, Jacqueline Batley, P. Igo-Kemenes, B. C. Shen, F. S. Merritt, E. Ros, D. R. Rust, M. J. Goodrick, I. Cohen, G. Duckeck, R. Ströhmer, G. Maringer, M. Hansroul, H. Jeremie, P. Lennert, C. M. Hawkes, M. Cooper, Daniel Lellouch, Horst Breuker, J. Mildenberger, Harold Nguyen, C. H. Shepherd-Themistocleous, T. P. Kokott, Carla Sbarra, A. D. Schaile, M. J. Oreglia, R. E. Hughes-Jones, U. Maur, J. A. McKenna, V. H. Winterer, Takehiko Mori, A. K. Honma, H. M. Bosch, Wolfram Dietrich Zeuner, O. Schaile, E. do Couto e Silva, D. A. Hinshaw, G. G. Hanson, N. I. Geddes, R. J. Homer, Margret Fincke-Keeler, R. F. McGowan, J. R. Carter, G. N. Patrick, W. G. Scott, P. M. Hattersley, R. Kowalewski, B. Boden, F. Odorici, M. Jimack, S. Bougerolle, J. Hart, P. F. Harrison, T. Hilse, O. Runolfsson, D. G. Fong, J. Gascon, H. von der Schmitt, P. Pfister, B. Poli, P. G. Estabrooks, S. Wotton, G. Giacomelli, E.J. Prebys, H. O. Ogren, Christoph Geich-Gimbel, A. Simon, Otmar Biebel, J. D. Gillies, G. E. Richards, John Allison, M. Hauschild, M. J. Losty, Claudio Grandi, D. G. Charlton, D. L. Wagner, T. Behnke, P. M. Watkins, J. W. Gary, M. S. Dixit, Frans Meijers, P. D. Acton, M. Yurko, Stephen Lloyd, H. M. Fischer, C. Markus, H. Deng, R. Humbert, P. W. Jeffreys, A. Yeaman, N. Paz-Jaoshvili, J. Kroll, R. G. Kellogg, A. M. Lee, N. K. Watson, P. Paschievici, S. Barnett, Marcello Mannelli, J. E. Duboscq, A. Michelini, A. C. Janissen, D. C. Imrie, W. R. Gibson, F. X. Gentit, R. J. Barlow, J. Banks, C. Jui, N. J. Tresilian, J. E. Conboy, Stefano Marcellini, James Letts, Andris Skuja, M. Tecchio, G. P. Siroli, Christoph Schwick, Erez Etzion, S. Weisz, R. D. Heuer, T. Kawamoto, Fabrizio Fabbri, D. Van den plas, A. Pouladdej, H. Mes, I. P. Duerdoth, A. Astbury, J. G. Layter, Tetsuro Mashimo, D. Hochman, N. J. Thackray, Stefan Kluth, Shlomit Tarem, A. Beck, S. Orito, Tohru Takeshita, O. Ganel, E. Heflin, A. J. Martin, M. Rosvick, G. A. Snow, C. P. Ward, C. Wahl, T. Mouthuy, S. Rossberg, C. J. Oram, Georges Azuelos, W. Gorn, R. M. Brown, F. G. Oakham, S. W. O'Neale, C. P. Howarth, Peter R Hobson, J. F. Kral, K. W. Bell, Lorne Levinson, R. P. Middleton, J. E. Pilcher, G. T. Zorn, N. Wermes, Ehud Duchovni, B. W. Kennedy, G. A. Bahan, C. K. Hargrove, F. Lamarche, R. Shypit, T. J. Smith, Max Weber, M. Jobes, U. Binder, R. J. Hemingway, A. M. Rossi, Misao Sasaki, P. Scharff-Hansen, G. Beaudoin, J. C. Clayton, T. Tsukamoto, S. Levegrün, P. Jovanovic, Austin Ball, D. Menszner, P. Mättig, Alessandro Montanari, Shlomo Dado, D. E. Plane, A. M. Smith, Stephen Hillier, G. Vasseur, B. Lorazo, H. Ihssen, X. C. Lou, I. J. Bloodworth, G. M. Dallavalle, Giora Mikenberg, Alan Watson, S. W. Gensler, D. J.P. Dumas, T. Kobayashi, M. Settles, M. Foucher, C. J. Virtue, G. W. Wilson, D. Karlen, Phillip Allport, M. Morri, K. Stephens, J. R. McNutt, Gideon Alexander, Paolo Capiluppi, P. Schenk, V. Gibson, G. Quast, John Baines, D. R. Ward, G. Transtromer, D. J. Miller, S. Schreiber, P. S. Wells, T. J. McMahon, Terry Richard Wyatt, M. Coupland, J. Schwiening, R. K. Carnegie, Richard Keeler, J. A. Wilson, Claude Leroy, J. P. Pansart, F. C. Grant, M. A. Whalley, W. Schappert, A. Buijs, D. M. Strom, J. von Krogh, Dave Robinson, L. A. del Pozo, Michael Dittmar, G. Yekutieli, A. A. Carter, John Hobbs, P. E.L. Clarke, J. Steuerer, R. Yaari, S. Bethke, Marco Cuffiani, P. A. Elcombe, D. L. Rees, J. Becker, G. J. VanDalen, A. Gaidot, M. Kuwano, T. Wlodek, M. Sproston, P. Routenburg, N. Tesch, A. Dieckmann, J. M. Lorah, W. Mohr, K. J. Anderson, C. Y. Chang, P. Taras, and Mitsuaki Nozaki
Subjects: Physics, Quark, Nuclear and High Energy Physics, Particle physics, Electron–positron annihilation, media_common.quotation_subject, Hadron, Charge (physics), Weinberg angle, Asymmetry, Standard Model, Nuclear physics, High Energy Physics::Experiment, Particle Physics - Experiment, media_common, Lepton
Abstract: We present a measurement of the forward-backward charge asymmetry in hadronic decays of the Z0 using data collected with the OPAL detector at LEP. The forward-backward charge asymmetry was measured using a weight function method which gave the number of forward events on a statistical basis. In a data sample of 448 942 hadronic Z0 decays, we have observed a charge asymmetry of Ah = 0.040±0.004 (stat.)±0.006 (syst.)±0.002 (B0 B 0 mix.), taking into account the effect of B0 B 0 mixing. In the framework of the standard model, this asymmetry corresponds to an effective weak mixing angle averaged over five quark flavours of sin 2 θ W = 0.2321 ± 0.0017 ( stat. ) ± 0.0027 ( syst. ) ± 0.0009 (B0 B 0 mix.). The result agrees with the value obtained from the Z0 line shape and lepton pair forward-backward asymmetry.
Published: 1992

34. A test of higher order electroweak theory in $Z^{0}$ decays to two leptons with an associated pair of charged particles

Author: J. Hart, B. C. Shen, M. F. Turner, A. K. Honma, J. D. Gillies, P. Poffenberger, H. Przysiezniak, W. G. Scott, M. Jimack, Gideon Bella, S. Barnett, D. R. Rust, John Allison, H. J. Burckhart, D. Hochman, N. J. Thackray, R. Kowalewski, Andris Skuja, Tetsuro Mashimo, Jacqueline Batley, G. Beaudoin, W. Gorn, G. A. Bahan, R. Mir, H. Oh, P. Lennert, R. J. Barlow, M. J. Losty, P. Igo-Kemenes, G. Maringer, K. Stephens, R. G. Kellogg, H. Jeremie, J. R. McNutt, R. E. Hughes-Jones, U. Maur, G. G. Hanson, H. Mes, I. P. Duerdoth, O. Runolfsson, Shlomo Dado, Stefano Marcellini, D. E. Klem, F. Lamarche, R. J. Hemingway, M. J. Oreglia, James Letts, G. Giacomelli, P. G. Estabrooks, E. do Couto e Silva, M. Hauschild, V. Gibson, Tohru Takeshita, E.J. Prebys, J. von Krogh, Phillip Allport, G. Quast, D. E. Plane, X. C. Lou, Paul Kyberd, John Baines, F. K. Loebinger, R. Van Kooten, D. Pitman, John Hobbs, P. Jovanovic, M. H. Lehto, Stephen Hillier, Claudio Grandi, M. Yurko, P. Singh, G. M. Dallavalle, Austin Ball, D. Menszner, M. W. Redmond, S. W. O'Neale, Giora Mikenberg, A. Astbury, P. Paschievici, P. M. Watkins, M. S. Dixit, Georges Azuelos, Dave Robinson, Frans Meijers, P. W. Jeffreys, K. J. Anderson, A. Rollnik, Peter R Hobson, D. R. Ward, H. O. Ogren, J. R. Carter, G. N. Patrick, A. Simon, Otmar Biebel, Christoph Geich-Gimbel, M. Hansroul, Alessandro Montanari, A. Gaidot, P. E.L. Clarke, J. F. Kral, L. A. del Pozo, S. Schreiber, K. W. Bell, W. J. Collins, T. J. McMahon, M. Kuwano, Alan Watson, G. Transtromer, A. M. Lee, Randall Sobie, G. D. Lafferty, N. I. Geddes, D. J.P. Dumas, R. W. L. Jones, J. Steuerer, G. E. Richards, D. G. Charlton, D. L. Wagner, M. Couch, C. Y. Chang, J. Schwiening, T. Wlodek, Sachio Komamiya, Max Weber, Gideon Alexander, Paolo Capiluppi, P. Schenk, Misao Sasaki, M. Sproston, D. J. Miller, E. Ros, B. Boden, B. Poli, P. Berlich, R. Humbert, J. P. Martin, R. K. Carnegie, L. Köpke, Silvia Arcelli, O. Ganel, W. R. Gibson, P. Taras, P. Le Du, N. Wermes, G. A. Snow, J. Mildenberger, Harold Nguyen, J. A. Wilson, John Hill, H. M. Fischer, A. J. Martin, T. P. Kokott, Rene Brun, Carla Sbarra, P. Routenburg, T. W. Pritchard, F. Odorici, C. P. Ward, A. Michelini, Ehud Duchovni, R. Shypit, S. De Jong, G. Duckeck, R. Ströhmer, A. C. Janissen, H. Takeda, W. Schappert, E. Heflin, B. Panzer-Steindel, H. Ihssen, N. Tesch, A. Dieckmann, T. Kawamoto, D. Strom, S. A. Robins, R. Yaari, F. G. Oakham, J. Banks, R. M. Brown, Lorne Levinson, N. J. Tresilian, G. T. Zorn, S. Bethke, Marco Cuffiani, S. W. Gensler, R. J. Homer, P. A. Elcombe, S. Weisz, R. D. Heuer, B. W. Kennedy, Fabrizio Fabbri, M. M. Deninno, S. Orito, C. Fukunaga, M. Rosvick, T. Kobayashi, C. J. Virtue, K. Riles, Michael Dittmar, T. Mouthuy, D. Van den plas, P. S. Wells, H. M. Bosch, G. Yekutieli, Margret Fincke-Keeler, Wolfram Dietrich Zeuner, A. A. Carter, D. L. Rees, J. Becker, A. M. Rossi, S. Bougerolle, T. Tsukamoto, J. Kroll, Terry Richard Wyatt, S. Levegrün, J. G. Layter, G. J. VanDalen, N. K. Watson, P. F. Harrison, A. D. Schaile, P. D. Acton, Stephen Lloyd, D. Axen, S. Sanghera, F. X. Gentit, C. K. Hargrove, V. H. Winterer, M. Coupland, F. C. Grant, S. R. Hou, C. Wahl, J. M. Lorah, M. A. Whalley, A. Jawahery, W. Mohr, J. E. Conboy, M. Ogg, P. Pfister, G. Tysarczyk-Niemeyer, C. P. Howarth, Peter Sherwood, A. Pouladdej, R. W. Springer, Alexander Wagner, J. E. Pilcher, C. Moisan, J. P. Walker, J. Hagemann, J. Ludwig, N. Paz-Jaoshvili, P. Teixeira-Dias, K. Runge, P. Bock, F. S. Merritt, A. Buijs, O. Schaile, J. A. McKenna, D. A. Hinshaw, R. F. McGowan, T. Behnke, Horst Breuker, Richard Keeler, Claude Leroy, J. P. Pansart, D. G. Fong, J. Gascon, H. von der Schmitt, J. W. Gary, Marcello Mannelli, J. E. Duboscq, M. Jobes, U. Binder, P. Scharff-Hansen, A. M. Smith, G. Vasseur, B. Lorazo, P. M. Hattersley, D. C. Imrie, G. P. Siroli, Christoph Schwick, Kiyotomo Kawagoe, I. J. Bloodworth, J. M. Roney, P. Weber, M. Settles, A. Beck, G. W. Wilson, D. Karlen, C. M. Hawkes, M. Cooper, Daniel Lellouch, Takehiko Mori, T. J. Smith, P. Mättig, S. Wotton, J. Goldberg, B. Nellen, P. Leblanc, H. G. Evans, M. J. Goodrick, I. Cohen, Erez Etzion, Gareth J. Barker, Shlomit Tarem, S. Rossberg, C. J. Oram, and R. P. Middleton
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Electroweak interaction, Invariant mass, Charged particle, Particle Physics - Experiment, Vertex (geometry), Lepton
Abstract: The OPAL detector at LEP was used to study the reactions e + e − → e + e − V, e + e − → μ + μ − V and e + e − → τ + τ − V, where V represents an additional pair of oppositely charged tracks coming directly from the event vertex. Rates for these processes were determined using selection criteria similar to those described in a recent publication by the ALEPH Collaboration in which a possible excess in the τ + τ − V channel was reported. In the OPAL data no discrepancy was found between the measured production rates and those expected from known physics processes in any of the three channels. The measured distributions of the invariant mass of the V and angle between the V and closest lepton are also described adequately within the context of the standard model.
Published: 1992

35. Search for free gluons in hadronic $Z^{0}$ decays

Author: T. Mouthuy, Andris Skuja, B. C. Shen, Tetsuro Mashimo, J. M. Lorah, John Hobbs, W. Mohr, R. Mir, A. M. Rossi, H. E. Stier, Erez Etzion, P. G. Estabrooks, C. Moisan, J. P. Walker, T. Tsukamoto, S. Levegrün, W. G. Scott, H. Oh, D. A. Hinshaw, P. Teixeira-Dias, Gareth J. Barker, W. Gorn, P. Igo-Kemenes, G. A. Bahan, H. O. Ogren, G. Maringer, D. C. Imrie, Christoph Geich-Gimbel, M. M. Deninno, Shlomit Tarem, J. Kroll, F. X. Gentit, J. E. Conboy, M. Ogg, A. Pouladdej, K. Stephens, P. M. Watkins, P. E.L. Clarke, D. E. Plane, P. A. Elcombe, C. M. Hawkes, M. Cooper, H. Jeremie, Daniel Lellouch, J. Hart, T. Behnke, Stephen Hillier, R. E. Hughes-Jones, U. Maur, F. S. Merritt, R. Shypit, Takehiko Mori, G. M. Dallavalle, G. P. Siroli, R. Kowalewski, J. R. McNutt, S. Rossberg, R. G. Kellog, J. A. McKenna, R. F. McGowan, I. Wingerter, A. K. Honma, M. J. Oreglia, J. P. Martin, Alan Watson, V. Gibson, R. P. Middleton, M. J. Losty, D. L. Rees, John Hill, N. I. Geddes, J. Mildenberger, D. J.P. Dumas, Harold Nguyen, S. De Jong, F. Odorici, Silvia Arcelli, G. Quast, B. B. Brabson, C. Fukunaga, J. Becker, John Baines, M. Hansroul, B. Boden, E. Ros, B. Poli, D. G. Fong, G. Duckeck, R. Ströhmer, J. Gascon, H. von der Schmitt, G. J. VanDalen, W. R. Gibson, I. J. Bloodworth, D. R. Ward, C. Ho, J. R. Carter, H. M. Fischer, G. N. Patrick, D. Strom, G. Eckerlin, A. Michelini, P. Debu, R. J. Homer, G. T. Zorn, G. Transtromer, A. C. Janissen, J. W. Gary, H. M. Bosch, T. P. Kokott, Rene Brun, Wolfram Dietrich Zeuner, P. Singh, J. L. Pinfold, S. Wotton, T. R. Yaari, O. Runolfsson, S. Bethke, Marco Cuffiani, J. von Krogh, Marcello Mannelli, M. Jobes, U. Binder, M. Settles, S. A. Robins, N. C. Wood, P. Scharff-Hansen, R. W. L. Jones, M. Weymann, A. Beck, Y. Yang, E. Heflin, R. M. Brown, Lorne Levinson, J. G. Layter, M. W. Moss, Paul Kyberd, F. K. Loebinger, B. P. O'Neill, D. Axen, A. Jawahery, G. Tysarczyk-Niemeyer, P. Le Du, H. Kreutzmann, B. W. Kennedy, S. Bougerolle, W. J. Collins, B. Panzer-Steindel, J. Banks, K. J. Anderson, P. F. Harrison, P. Ashton, Dave Robinson, Peter Sherwood, R. W. Springer, Alexander Wagner, J. Hagemann, J. Ludwig, G. D. Lafferty, Tohru Takeshita, P. D. Acton, P. Pfister, Stephen Lloyd, W. J. Larson, G. W. Wilson, D. Karlen, Claudio Grandi, K. Runge, P. Bock, F. Lamarche, A. Gaidot, M. Kuwano, M. Sproston, P. Routenburg, R. J. Hemingway, T. W. Pritchard, A. Dieckmann, Gideon Bella, H. J. Burckhart, S. Weisz, R. D. Heuer, Jacqueline Batley, P. M. Hattersley, L. A. del Pozo, C. Sbarra, M. W. Redmond, G. A. Snow, C. P. Ward, A. M. Smith, H. Mes, Georges Azuelos, S. Sanghera, B. Holl, P. Jovanovic, I. P. Duerdoth, G. Vasseur, N. Wermes, Michael Dittmar, Kiyotomo Kawagoe, Austin Ball, J. Goldberg, C. Y. Chang, Fabrizio Fabbri, D. Van den plas, B. Lorazo, G. Yekutieli, D. Menszner, A. Rollnik, J. F. Kral, K. W. Bell, G. Beaudoin, T. J. Smith, Max Weber, Ehud Duchovni, I. Zacharov, Alessandro Montanari, B. Nellen, P. Schenk, A. D. Schaile, P. Taras, Misao Sasaki, Horst Breuker, N. K. Watson, P. Leblanc, J. M. Roney, A. A. Carter, P. Mättig, H. Ihssen, M. Rosvick, D. R. Rust, Shlomo Dado, D. Pitman, Mitsuaki Nozaki, S. Komamiya, V. H. Winterer, P. Weber, G. G. Hanson, H. Takeda, X. C. Lou, R. Sobie, A. Astbury, P. Lennert, F. G. Oakham, S. W. Gensler, T. Kobayashi, S. R. Hou, Giora Mikenberg, O. Ganel, M. Jimack, M. J. Goodrick, H. Przysiezniak, John Allison, J. D. Gillies, A. J. Martin, S. Schreiber, T. J. McMahon, I. Cohen, S. W. O'Neale, Peter R Hobson, R. J. Barlow, M. Yurko, D. E. Klem, J. Schwiening, R. K. Carnegie, P. W. Jeffreys, G. Giacomelli, Phillip Allport, K. Riles, J. A. Wilson, R. Van Kooten, M. Fincke-Keeler, A. M. Lee, M. H. Lehto, E.J. Prebys, W. Schappert, C. K. Hargrove, C. J. Oram, M. S. Dixit, Frans Meijers, S. J. Pawley, P. Berlich, Gideon Alexander, Stefano Marcellini, Claus Kleinwort, L. Köpke, Paolo Capiluppi, James Letts, A. Simon, Otmar Biebel, D. G. Charlton, M. Couch, R. Humbert, T. Kawamoto, S. Orito, D. Hochman, N. J. Thackray, C. Wahl, C. P. Howarth, J. E. Pilcher, O. Schaile, M. Hauschild, P. Paschievici, D. J. Miller, P R Poffenberger, P. S. Wells, C. J. Virtue, M. Coupland, Richard Keeler, Claude Leroy, J. P. Pansart, F. C. Grant, M. A. Whalley, A. Buijs, and M. F. Turner
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Electron–positron annihilation, Monte Carlo method, Hadron, Detector, High Energy Physics::Experiment, Lower limit, Particle Physics - Experiment, Gluon
Abstract: A search was performed for isolated, neutral, highly energetic particles which interact hadronically with matter. The data sample consists of 134 278 multihadronic events observed by the OPAL detector at LEP in e + e − collisions with centre-of-mass energies around the Z 0 pole. Our study is sensitive to events predicted by a model in which gluons appear as free, stable, particles. We observed two events and derive a lower limit at 95% confidence level of 47 GeV on the barrier height V m of a potential well introduced by this model. A Monte Carlo simulation of standard multihadronic Z 0 decays predicts 3.3 events.
Published: 1991

36. Properties of multihadronic events with a final state photon at $\sqrt{s} = M_{Z0}$

Author: G. Beaudoin, Shlomo Dado, X. C. Lou, Giora Mikenberg, N. C. Wood, Andris Skuja, A. Simon, G. A. Snow, Otmar Biebel, C. P. Ward, H. Takeda, Tetsuro Mashimo, D. G. Charlton, B. C. Shen, J. von Krogh, F. G. Oakham, P. Singh, J. G. Layter, H. O. Ogren, M. Couch, J. Banks, A. K. Honma, W. G. Scott, Christoph Geich-Gimbel, S. Weisz, R. D. Heuer, M. M. Deninno, Kiyotomo Kawagoe, W. Gorn, T. Mouthuy, D. E. Plane, A. Gaidot, R. Humbert, Fabrizio Fabbri, J. Kroll, J. M. Roney, R. W. L. Jones, R. Kowalewski, M. Kuwano, A. D. Schaile, N. Wermes, D. Van den plas, Ehud Duchovni, G. A. Bahan, H. Przysiezniak, M. Sproston, P. Weber, M. J. Losty, Paul Kyberd, F. K. Loebinger, M. Jobes, U. Binder, P. Scharff-Hansen, M. Yurko, P. Ashton, Dave Robinson, F. X. Gentit, J. E. Conboy, M. Ogg, P. Routenburg, R. Shypit, P. W. Jeffreys, T. Kawamoto, O. Schaile, M. W. Redmond, S. Sanghera, W. J. Larson, L. A. del Pozo, S. Schreiber, T. J. McMahon, P. S. Wells, C. J. Virtue, Terry Richard Wyatt, Stephen Hillier, G. M. Dallavalle, H. Ihssen, P. Le Du, H. Kreutzmann, V. H. Winterer, A. M. Lee, A. Rollnik, M. Hansroul, A. Dieckmann, A. Pouladdej, D. R. Rust, J. Schwiening, R. K. Carnegie, B. Panzer-Steindel, S. Orito, J. D. Gillies, K. J. Anderson, M. Rosvick, P. E.L. Clarke, S. W. Gensler, J. A. Wilson, M. Coupland, P. A. Elcombe, D. J.P. Dumas, R. Mir, H. Mes, H. Oh, F. S. Merritt, P. Lennert, S. R. Hou, A. M. Smith, R. J. Barlow, D. J. Miller, T. Kobayashi, K. Stephens, D. E. Klem, H. E. Stier, I. P. Duerdoth, G. Vasseur, J. R. McNutt, Gideon Bella, W. Schappert, D. Axen, Tohru Takeshita, B. Lorazo, R. J. Homer, G. G. Hanson, M. F. Turner, P. G. Estabrooks, D. L. Rees, R. Yaari, S. Bethke, J. A. McKenna, R. K. Keeler, Marco Cuffiani, J. Becker, C. Fukunaga, J. Mildenberger, Harold Nguyen, S. W. O'Neale, S. Bougerolle, H. J. Burckhart, Jacqueline Batley, A. Jawahery, F. Lamarche, Peter R Hobson, N. I. Goddes, M. J. Oreglia, Georges Azuelos, P. Poffenberger, A. M. Rossi, Phillip Allport, B. B. Brabson, Margret Fincke-Keeler, V. Gibson, R. J. Hemingway, D. G. Fong, J. F. Kral, R. F. McGowan, K. W. Bell, G. Quast, J. Gascon, R. Van Kooten, T. Tsukamoto, S. Levegrün, C. Wahl, G. Giacomelli, D. Pitman, Max Weber, H. von der Schmitt, John Baines, O. Runolfsson, J. R. Carter, M. H. Lehto, G. N. Patrick, H. M. Fischer, Michael Dittmar, G. Eckerlin, G. Yekutieli, J. C. Hill, Misao Sasaki, C. P. Howarth, P. M. Watkins, P. Jovanovic, E.J. Prebys, T. J. Smith, Austin Ball, D. Menszner, W. R. Gibson, J. W. Gary, John Hobbs, C. Ho, Claudio Grandi, A. Michelini, A. C. Janissen, J. E. Pilcher, Marcello Mannelli, P. Pfister, M. Jimack, G. Tysarczyk-Niemeyer, Alessandro Montanari, Claude Leroy, Gideon Alexander, Paolo Capiluppi, P. Schenk, D. R. Ward, John Allison, M. W. Moss, G. Transtromer, A. Beck, B. P. O'Neill, J. P. Pansart, M. S. Dixit, Frans Meijers, E. Heflin, A. A. Carter, C. Y. Chang, R. M. Brown, J. M. Lorah, F. C. Grant, M. A. Whalley, P. M. Hattersley, J. Hart, Lorne Levinson, M. Hauschild, Peter Sherwood, R. G. Kellogg, W. Mohr, P. Taras, B. W. Kennedy, Mitsuaki Nozaki, Y. Yang, P. Paschievici, Stefano Marcellini, S. A. Robins, J. P. Martin, A. Buijs, C. Moisan, J. P. Walker, J. L. Pinfold, James Letts, S. J. Pawley, P. Teixeira-Dias, D. C. Imrie, P. F. Harrison, P. Berlich, S. De Jong, P. Mättig, P. D. Acton, Stephen Lloyd, I. Wingerter, Claus Kleinwort, L. Köpke, G. P. Siroli, P. Debu, Silvia Arcelli, W. J. Collins, R. W. Springer, Alexander Wagner, Randall Sobie, G. D. Lafferty, J. Hagemann, J. Ludwig, G. J. Van Dalen, N. K. Watson, D. Hochman, N. J. Thackray, K. Runge, P. Bock, F. Odorici, Sachio Komamiya, T. W. Pritchard, E. Ros, A. T. Watson, T. P. Kokott, Rene Brun, C. M. Hawkes, M. Cooper, B. Boden, B. Poli, S. Wotton, Daniel Lellouch, M. Weymann, P. Igo-Kemenes, G. Maringer, H. Jeremie, R. E. Hughes-Jones, U. Maur, Takehiko Mori, D. A. Hinshaw, J. Goldberg, B. Nellen, T. Behnke, P. Leblanc, B. Holl, I. J. Bloodworth, M. J. Goodrick, G. Duckeck, R. Ströhmer, I. Cohen, D. Strom, G. T. Zorn, I. Zacharov, M. Settles, H. M. Bosch, Wolfram Dietrich Zeuner, Horst Breuker, Erez Etzion, Gareth J. Barker, G. W. Wilson, Shlomit Tarem, D. Karlen, S. Rossberg, C. J. Oram, R. P. Middleton, A. Astbury, O. Ganel, A. J. Martin, K. Riles, and C. K. Hargrove
Subjects: Physics, Quantum chromodynamics, Jet (fluid), Particle physics, Photon, Physics and Astronomy (miscellaneous), Strong interaction, Hadron, Nuclear physics, Yield (chemistry), High Energy Physics::Experiment, Constant (mathematics), Engineering (miscellaneous), Event (particle physics), Particle Physics - Experiment
Abstract: The properties of final state photons in multihadronic decays of theZ0 and those of the recoiling hadronic system are discussed and compared with theoretical expectations. The yield of two and three jet events with final state photons is found to be in good agreement with the expectation from a matrix element calculation ofO(ααs. Uncertainties in the interpretation of the theoretical calculation do not yet permit a final assessment of events with just one reconstructed jet. Comparing the rates of two jet events with a photon to those of three jet events in the inclusive multihadronic sample, the strong coupling constant in second order is determined asαs$(M_{Z^0 } )$=0.122±0.010, taking into account only the statistical and experimental systematic errors. It is found that an abelian model of the strong interaction does not describe the data. The comparison of the total yield and the jet rates with QCD shower programs shows better agreement with the ARIADNE model than with the JETSET model. Both programs are found to describe well the photon properties and the properties of the residual hadronic event.
Published: 1991

37. Decay mode independent search for a light Higgs boson and new scalars

Author: Takehiko Mori, M. Jobes, R. P. Middleton, P. Scharff-Hansen, W. J. Larson, B. C. Shen, H. Ihssen, F. S. Merritt, L. Levinson, J. M. Lorah, R. Van Kooten, O. Schaile, M. H. Lehto, A. M. Smith, O. Ganel, K. Riles, D. Karlen, A. Dieckmann, J. Goldberg, T. J. Smith, I. J. Bloodworth, C. Moisan, James D Gillies, M. Settles, E. Duchovni, G. Eckerlin, G. P. Siroli, G. Beaudoin, U. Maur, B. Nellen, R. M. Brown, Phillip Allport, Andris Skuja, P. Mättig, J. A. McKenna, S. J. Pawley, Gunter Quast, N. C. Wood, S. Levegrün, Claus Kleinwort, G. W. Wilson, F. C. Grant, M. A. Whalley, L. Köpke, G. Tysarczyk-Niemeyer, D. G. Charlton, Sachio Komamiya, R. W.L. Jones, P. Singh, A. M. Lee, Kiyotomo Kawagoe, A. Beck, J. P. Martin, P. Bock, D. Strom, M. Couch, G. T. Zorn, L. Lessard, B. P. O'Neill, J. Ludwig, Tetsuro Mashimo, C. P. Howarth, A. Buijs, E. Ros, J. Becker, K. Stephens, P. Teixeira-Dias, D. E. Plane, W. R. Gibson, E. Etzion, M. Kuwano, Stephen Hillier, J. Gascon, K. J. Anderson, C. J. Oram, J. M. Roney, J. E. Pilcher, R. Yaari, G. Maringer, J. C. Armitage, J. Hagemann, P. Jovanovic, Wolfram Dietrich Zeuner, P. Pfister, J. von Krogh, R. F. McGowan, O. Biebel, M. Jimack, John Allison, A. Michelini, G. N. Patrick, R. Shypit, G. Transtromer, G. A. Snow, C. P. Ward, A. J. Martin, Rene Brun, B. Holl, G. M. Dallavalle, R. Ströhmer, R. Kowalewski, S. Schreiber, J. T.M. Chrin, P. Weber, T. P. Kokott, Austin Ball, W. Schappert, W. G. Scott, P. Ashton, W. Gorn, N. Wermes, J. Mildenberger, Dave Robinson, P. D. Acton, C. Y. Chang, M. S. Dixit, P. Kyberd, Paolo Capiluppi, G. Yekutieli, G. A. Bahan, J. Banks, G. Azuelos, A. D. Schaile, P. A. Elcombe, H. O. Ogren, I. Zacharov, Horst Breuker, Alan Watson, L. A. del Pozo, Alessandro Montanari, T. Kawamoto, Mitsuaki Nozaki, J. Hart, Tohru Takeshita, R. G. Kellogg, S. Rossberg, M. Hauschild, M. Coupland, M. M. Deninno, J. P. Walker, P. Poffenberger, J. D. Hobbs, S. Weisz, R. D. Heuer, E. Gross, Fabrizio Fabbri, P. Paschievici, D. Van den plas, P. Igo-Kemenes, D. L. Rees, G. G. Hanson, H. E. Stier, Richard Keeler, G. Alexander, Y. Yang, P. F. Harrison, J. Kroll, D. Axen, Stefano Marcellini, D. J.P. Dumas, S. Orito, F. X. Gentit, G. J. VanDalen, P. M. Watkins, James Letts, P. Leblanc, D. Hochman, R. Mir, B. B. Brabson, H. Oh, D. G. Fong, H. Takeda, V. Gibson, U. Binder, Michael Dittmar, D. J. Miller, P. Routenburg, H. von der Schmitt, J. E. Conboy, W. Mohr, Stephen Lloyd, D. R. Rust, P. W. Jeffreys, M. Cooper, X. C. Lou, M. Sproston, P. Lennert, M. W. Moss, B. Boden, J. L. Pinfold, T. W. Pritchard, A. Wagner, John Baines, J. W. Gary, R. K. Carnegie, R. Sobie, A. Jawahery, I. Wingerter, S. Sanghera, M. F. Turner, P. S. Wells, Silvia Arcelli, P. E.L. Clarke, T. Behnke, Misao Sasaki, N. K. Watson, D. E. Klem, E.J. Prebys, Harold Nguyen, P. M. Hattersley, P. Schenk, D. Menszner, C. K. Hargrove, A. Rollnik, Peter Sherwood, F. G. Oakham, H. Jeremie, H. Kreutzmann, R. W. Springer, G. Duckeck, P. Taras, S. Bougerolle, S. Dado, H. M. Fischer, T. J. McMahon, Marcello Mannelli, A. A. Carter, M. Ogg, M. J. Oreglia, V. H. Winterer, C. Ho, B. Poli, R. E. Hughes-Jones, J. R. McNutt, N. I. Geddes, R. J. Barlow, F. Odorici, J. Schwarz, D. R. Ward, J. R. Carter, E. Heflin, J. P. Pansart, A. Gaidot, M. J. Goodrick, M. Hansroul, S. W. Gensler, T. Kobayashi, J. A. Wilson, P. Le Du, Frans Meijers, D. A. Hinshaw, T. Mouthuy, Richard J Hemingway, G. J. Barker, S. Bethke, B. W. Kennedy, G. Vasseur, S. Wotton, I. Cohen, A. Simon, M. Weymann, B. Panzer-Steindel, S. W. O'Neale, H. Mes, R. J. Homer, O. Runolfsson, F. K. Loebinger, Peter R Hobson, Marco Cuffiani, H. M. Bosch, D. C. Imrie, J. G. Layter, L. Janissen, I. P. Duerdoth, F. Lamarche, G. Giacomelli, M. W. Redmond, Claudio Grandi, H. Przysiezniak, A. M. Rossi, P. Debu, T. Tsukamoto, A. Pouladdej, G. Mikenberg, Gideon Bella, A. Astbury, H. J. Burckhart, Jacqueline Batley, R. Humbert, John Hill, S. De Jong, C. Geich-Gimbel, S. A. Robins, M. J. Losty, M. Fincke-Keeler, K. Runge, C. J. Virtue, M. Weber, N. J. Thackray, T. R. Wyatt, S. Tarem, S. R. Hou, C. Fukunaga, C. Wahl, C. Leroy, B. Lorazo, W. J. Collins, G. D. Lafferty, K. W. Bell, P. G. Estabrooks, C. M. Hawkes, and Daniel Lellouch
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, High Energy Physics::Phenomenology, Scalar (mathematics), Elementary particle, Scalar boson, Higgs field, symbols.namesake, symbols, Higgs boson, High Energy Physics::Experiment, Higgs mechanism, Particle Physics - Experiment, Minimal Supersymmetric Standard Model, Boson
Abstract: Using data from e + e − collisions collected with the OPAL detector during the 1990 LEP run, a search was mode for a low mass Higgs boson (H 0 ) with arbitrary decay mode. The existence of a minimal standard model H 0 with mass in the range 0 ⩽ m H ⩽ 11.3 GeV/ c 2 is excluded at the 95% confidence level for all possible decay modes of the H 0 . Limits on the production of Higgs bosons predicted by the minimal supersymmetric standard model and new scalar particles that couple to the Z 0 are presented as a function of the scalar mass.
Published: 1991

38. A study of Bose-Einstein correlations in $e^{+}e^{-}$ annihilations at LEP

Author: A. Simon, Otmar Biebel, D. G. Charlton, M. Couch, N. C. Wood, R. Humbert, J. T.M. Chrin, P. W. Jeffreys, J. Hart, T. Kawamoto, A. M. Lee, G. A. Snow, C. P. Ward, P. Pfister, O. Schaile, S. Orito, John H. Schwarz, Y. Yang, R. Mir, H. Oh, P. F. Harrison, J. C. Armitage, P. D. Acton, Stephen Lloyd, P. Igo-Kemenes, G. Maringer, H. Jeremie, R. E. Hughes-Jones, U. Maur, Andris Skuja, G. Beaudoin, M. J. Oreglia, D. R. Rust, J. M. Lorah, P. Lennert, W. Mohr, J. R. Carter, G. N. Patrick, Phillip Allport, Shlomo Dado, C. Wahl, F. S. Merritt, H. Przysiezniak, C. M. Hawkes, M. Cooper, Daniel Lellouch, Gideon Bella, Tetsuro Mashimo, P. A. Elcombe, C. P. Howarth, X. C. Lou, M. Hansroul, J. E. Pilcher, R. Van Kooten, M. H. Lehto, F. Odorici, D. E. Klem, D. L. Rees, D. E. Plane, H. J. Burckhart, J. Becker, Jacqueline Batley, Giora Mikenberg, Stephen Hillier, Michael Dittmar, G. J. VanDalen, G. M. Dallavalle, M. Hauschild, R. J. Homer, D. Hochman, N. J. Thackray, Gideon Alexander, J. A. McKenna, J. D. Hobbs, G. Yekutieli, P. Paschievici, K. Stephens, J. R. McNutt, O. Runolfsson, Paolo Capiluppi, S. J. Pawley, Claus Kleinwort, L. Köpke, E. K. U. Gross, Alan Watson, W. Gorn, A. Gaidot, D. J.P. Dumas, P. E.L. Clarke, T. Behnke, L. Lessard, C. Moisan, M. Kuwano, M. F. Turner, N. Wermes, G. G. Hanson, R. F. McGowan, M. Sproston, P R Poffenberger, V. Gibson, D. C. Imrie, J. P. Walker, J. Banks, P. Routenburg, A. Dieckmann, John Baines, Ehud Duchovni, A. A. Carter, P. Teixeira-Dias, S. Weisz, R. D. Heuer, Fabrizio Fabbri, Claudio Grandi, H. Mes, I. P. Duerdoth, D. Van den plas, J. D. Gillies, R. Shypit, H. O. Ogren, G. A. Bahan, P. S. Wells, C. J. Virtue, D. R. Ward, G. Transtromer, Christoph Geich-Gimbel, H. Ihssen, M. M. Deninno, D. A. Hinshaw, J. Kroll, E.J. Prebys, P. Schenk, F. X. Gentit, R. Yaari, S. Bethke, Marco Cuffiani, S. W. Gensler, C. Y. Chang, L. Janissen, W. R. Gibson, M. Coupland, J. E. Conboy, T. Kobayashi, C. Ho, M. Ogg, G. P. Siroli, P. Taras, P. Singh, A. Beck, E. Heflin, M. Jobes, U. Binder, A. Pouladdej, M. S. Dixit, S. Schreiber, Frans Meijers, R. M. Brown, Lorne Levinson, Mitsuaki Nozaki, R. J. Barlow, B. W. Kennedy, P. Scharff-Hansen, T. J. McMahon, R. W. L. Jones, D. J. Miller, Richard Keeler, P. Le Du, W. J. Larson, R. K. Carnegie, H. Kreutzmann, B. Panzer-Steindel, R. J. Sobie, J. P. Martin, John Hill, J. W. Gary, J. A. Wilson, S. De Jong, G. Giacomelli, W. Schappert, A. M. Smith, P. Debu, Claude Leroy, J. P. Pansart, N. K. Watson, F. C. Grant, G. Vasseur, M. A. Whalley, B. Lorazo, J. von Krogh, J. G. Layter, M. W. Moss, F. Lamarche, P. Ashton, Dave Robinson, B. B. Brabson, A. Buijs, D. G. Fong, L. A. del Pozo, P. M. Hattersley, R. J. Hemingway, J. Gascon, S. Sanghera, H. von der Schmitt, Kiyotomo Kawagoe, K. J. Anderson, A. P. Wagner, Marcello Mannelli, J. M. Roney, P. Jovanovic, P. Weber, S. W. O'Neale, Peter R Hobson, Austin Ball, D. Menszner, Sachio Komamiya, E. Ros, Alessandro Montanari, T. P. Kokott, Rene Brun, Tohru Takeshita, H. Takeda, Georges Azuelos, K. W. Bell, F. G. Oakham, Max Weber, Misao Sasaki, B. C. Shen, G. Duckeck, R. Ströhmer, D. Strom, W. G. Scott, G. T. Zorn, R. Kowalewski, H. M. Bosch, Wolfram Dietrich Zeuner, M. J. Losty, D. Axen, A. Jawahery, G. Tysarczyk-Niemeyer, Peter Sherwood, R. W. Springer, J. Ludwig, K. Runge, P. Bock, J. Goldberg, B. Nellen, P. Leblanc, M. J. Goodrick, I. Cohen, Erez Etzion, Gareth J. Barker, Shlomit Tarem, S. Rossberg, C. J. Oram, C. Milstene, R. P. Middleton, M. Jimack, John Allison, B. Holl, R. G. Kellogg, B. P. O'Neill, Stefano Marcellini, James Letts, I. Zacharov, J. Hagemann, Horst Breuker, Paul Kyberd, F. K. Loebinger, M. W. Redmond, A. Rollnik, J. Mildenberger, Harold Nguyen, Gunter Quast, H. E. Stier, P. G. Estabrooks, S. Bougerolle, W. J. Collins, G. D. Lafferty, P. M. Watkins, I. Wingerter, Silvia Arcelli, T. W. Pritchard, A. Astbury, H. M. Fischer, O. Ganel, A. Michelini, A. J. Martin, A. D. Schaile, K. Riles, S. Wotton, G. Eckerlin, M. Weymann, S. A. Robins, C. K. Hargrove, V. H. Winterer, T. R. Wyatt, S. R. Hou, T. Mouthuy, C. Fukunaga, J. L. Pinfold, A. M. Rossi, T. Tsukamoto, S. Levegrün, Takehiko Mori, N. I. Geddes, B. Boden, B. Poli, T. J. Smith, P. Mättig, I. J. Bloodworth, M. Settles, G. W. Wilson, D. Karlen, and Margret Fincke-Keeler
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Electron–positron annihilation, Hadron, Detector, Function (mathematics), Bose–Einstein correlations, Radius, Nuclear physics, Pion, High Energy Physics::Experiment, Particle Physics - Experiment
Abstract: Bose-Einstein correlations between like-sign charged track pairs have been studied in e + e − annihilation hadronic events at centre-of-mass energies around the Z 0 peak as a function of Q , the four-momentum difference of the pair. The measurement was performed with the OPAL detector at LEP. Assuming the charged tracks to be pions, the observed Bose-Einstein enhancement was used to extract the values of the strength of the effect and the radius of the pion emitting source, which were found to be λ =0.866±0.032±0.140 and R 0 =0.928±0.019±0.150 fm, respectively, where the first error is statistical and the second is systematic. The results do not show significant variation in comparison to e + e − annihilation measurements at lower centre-of-mass energies. If non-pion track contamination is taken into account, the value of the strength λ becomes consistent with unity.
Published: 1991

39. Observation of $J/\psi$ production in multihadronic $Z^{0}$ decays

Author: A. Astbury, O. Ganel, F. Lamarche, R. J. Hemingway, P. Jovanovic, Austin Ball, D. Menszner, Alessandro Montanari, P. Igo-Kemenes, G. Maringer, N. C. Wood, A. J. Martin, K. Riles, J. D. Hobbs, H. Jeremie, G. A. Snow, C. P. Ward, C. K. Hargrove, G. G. Hanson, R. Sobie, C. Milstene, G. Giacomelli, H. M. Fischer, R. E. Hughes-Jones, U. Maur, E.J. Prebys, E. K. U. Gross, A. Gaidot, M. Kuwano, F. Odorici, M. Jimack, John Allison, P. Routenburg, A. Michelini, M. S. Dixit, H. Przysiezniak, H. Takeda, G. N. Patrick, F. G. Oakham, R. G. Kellogg, J. D. Gillies, R. F. McGowan, A. Dieckmann, R. J. Barlow, S. A. Robins, Stefano Marcellini, H. O. Ogren, G. Beaudoin, Christoph Geich-Gimbel, N. K. Watson, Shlomo Dado, Frans Meijers, M. W. Moss, B. Holl, O. Schaile, X. C. Lou, C. M. Hawkes, M. Cooper, Daniel Lellouch, R. Shypit, Takehiko Mori, H. E. Stier, J. Goldberg, M. M. Deninno, B. Nellen, P. G. Murphy, C. Y. Chang, J. G. Layter, Giora Mikenberg, I. Zacharov, J. Kroll, P. Taras, P. G. Estabrooks, P. Leblanc, P. M. Hattersley, Mitsuaki Nozaki, Horst Breuker, F. X. Gentit, J. E. Conboy, H. Mes, I. P. Duerdoth, M. Ogg, D. R. Rust, P. M. Watkins, S. W. O'Neale, Peter R Hobson, W. R. Gibson, S. Sanghera, Paul Kyberd, F. K. Loebinger, A. Pouladdej, C. Ho, N. Wermes, T. Mouthuy, P. Schenk, A. D. Schaile, P. Lennert, P. A. Elcombe, D. A. Hinshaw, L. Janissen, P. W. Jeffreys, P. Pfister, A. Beck, A. M. Lee, M. J. Goodrick, I. Wingerter, Ehud Duchovni, D. E. Klem, Silvia Arcelli, E. Heflin, M. W. Redmond, I. Cohen, R. M. Brown, Lorne Levinson, V. H. Winterer, D. L. Rees, J. Becker, B. W. Kennedy, A. M. Rossi, A. Rollnik, K. J. Anderson, J. C. Armitage, G. J. VanDalen, H. Ihssen, T. Tsukamoto, S. Levegrün, M. Jobes, U. Binder, S. R. Hou, D. Hochman, N. J. Thackray, D. E. Plane, S. W. Gensler, Stephen Hillier, C. Moisan, J. P. Walker, Michael Dittmar, C. Wahl, G. Yekutieli, T. Kobayashi, S. Wotton, G. M. Dallavalle, K. Stephens, S. Bougerolle, J. R. McNutt, P. Teixeira-Dias, P. Scharff-Hansen, W. J. Collins, P. E.L. Clarke, T. Behnke, M. Weymann, A. A. Carter, Gunter Quast, D. J.P. Dumas, O. Runolfsson, W. J. Larson, C. P. Howarth, J. Mildenberger, Harold Nguyen, F. S. Merritt, L. Lessard, G. D. Lafferty, J. W. Gary, Phillip Allport, Claudio Grandi, J. M. Lorah, J. E. Pilcher, V. Gibson, R. Mir, T. W. Pritchard, N. I. Geddes, G. Eckerlin, A. M. Smith, H. Oh, W. Mohr, John Baines, B. Poli, R. Yaari, Erez Etzion, S. Bethke, Marco Cuffiani, G. Vasseur, B. Lorazo, Richard Keeler, Gideon Alexander, Paolo Capiluppi, Gareth J. Barker, Shlomit Tarem, D. R. Ward, J. Hart, J. Banks, P. Bock, B. C. Shen, Andris Skuja, S. Rossberg, D. C. Imrie, S. Weisz, R. D. Heuer, J. von Krogh, Y. Yang, Claude Leroy, W. G. Scott, Fabrizio Fabbri, J. P. Pansart, C. Fukunaga, P. F. Harrison, C. J. Virtue, G. P. Siroli, J. P. Martin, M. A. Whalley, D. Van den plas, R. P. Middleton, Tetsuro Mashimo, R. Kowalewski, R. Van Kooten, S. De Jong, P. Ashton, Dave Robinson, M. F. Turner, Sachio Komamiya, A. T. Watson, T. P. Kokott, Rene Brun, W. Gorn, M. J. Losty, S. Schreiber, T. J. McMahon, R. K. Carnegie, M. Hauschild, P. Paschievici, A. Buijs, P. Debu, I. J. Bloodworth, J. L. Pinfold, M. J. Oreglia, M. H. Lehto, C. J. Oram, P R Poffenberger, J. A. Wilson, M. Fincke-Keeler, M. Settles, M. Hansroul, Tohru Takeshita, G. A. Bahan, D. J. Miller, W. Schappert, S. J. Pawley, Claus Kleinwort, L. Köpke, Georges Azuelos, J. R. Carter, M. Sproston, P. S. Wells, G. Duckeck, G. W. Wilson, D. Karlen, R. J. Homer, K. W. Bell, B. P. O'Neill, Terry Richard Wyatt, D. Strom, J. Hagemann, M. Coupland, G. T. Zorn, Kiyotomo Kawagoe, B. B. Brabson, Max Weber, J. C. Hill, Misao Sasaki, A. P. Wagner, J. M. Roney, D. G. Fong, H. M. Bosch, Wolfram Dietrich Zeuner, J. Gascon, H. von der Schmitt, H. J. Bruckhart, Marcello Mannelli, A. Simon, T. J. Smith, Otmar Biebel, D. G. Charlton, M. Couch, P. Singh, R. Humbert, P. Mättig, J. T.M. Chrin, T. Kawamoto, S. Orito, John H. Schwarz, R. W. L. Jones, D. Axen, A. Jawahery, G. Tysarczyk-Niemeyer, Peter Sherwood, R. W. Springer, J. Ludwig, K. Runge, P. Le Du, H. Kreutzmann, B. Panzer-Steindel, Gideon Bella, Jacqueline Batley, and Stephen Lloyd
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Distribution (mathematics), Energy distribution, Meson, Branching fraction, Electron–positron annihilation, Hadron, High Energy Physics::Experiment, Production (computer science), Particle Physics - Experiment
Abstract: The production of J/ψ mesons in multihadronic Z0 decays has been observed in the e+e− and β+β− final states. From a sample of approximately 45 reconstructed J ψ mesons, the inclusive branching fraction is measured to be Br(Z0→J/ψ + X) = (4.5±0.8±0.4±0.6) × 10−3, where the first error is statistical, the second systematic, and the third error is due to the uncertainty in the leptonic decay rate of the J/ψ. The J/ψ energy distribution is consistent with the distribution expected from B hadron decays. The average B hadron lifetime is calculated from the measured distances between the primary and J/ψ vertices, resulting in τB = 1.32−0.25+0.31±0.15 ps, where the first error is statistical and the second systematic.
Published: 1991

40. A study of $K_{S}^{0}$ production in $Z^{0}$ decays

Author: J. R. McNutt, C. Milstene, W. G. Scott, Sachio Komamiya, A. T. Watson, I. J. Bloodworth, N. C. Wood, J. Goldberg, B. Nellen, A. Simon, R. Kowalewski, V. Gibson, Otmar Biebel, H. O. Ogren, John Baines, F. Odorici, G. A. Snow, C. P. Ward, R. J. Sobie, Christoph Geich-Gimbel, T. P. Kokott, Rene Brun, G. Maringer, G. Beaudoin, C. Y. Chang, Shlomo Dado, P. Leblanc, M. Settles, X. C. Lou, P. G. Murphy, Giora Mikenberg, Michael Dittmar, H. M. Fischer, G. Yekutieli, D. G. Charlton, D. A. Hinshaw, H. Jeremie, P. Taras, M. Couch, M. J. Goodrick, M. M. Deninno, I. Cohen, Claude Leroy, J. Kroll, R. Humbert, Mitsuaki Nozaki, Silvia Arcelli, R. E. Hughes-Jones, U. Maur, D. R. Ward, M. J. Losty, P. Igo-Kememes, J. P. Martin, A. A. Carter, A. Michelini, J. P. Pansart, F. X. Gentit, J. E. Conboy, H. Takeda, S. De Jong, M. Ogg, Phillip Allport, J. T.M. Chrin, G. W. Wilson, B. P. O'Neill, M. A. Whalley, C. Wahl, F. G. Oakham, E. K. U. Gross, A. Gaidot, M. Hansroul, A. Pouladdej, M. Kuwano, B. Panzer-Steindel, J. Hagemann, D. R. Rust, M. Sproston, F. S. Merritt, T. Kawamoto, A. Buijs, P. Singh, P. Debu, S. W. O'Neale, Peter R Hobson, C. P. Howarth, P. Routenburg, Erez Etzion, S. Orito, John H. Schwarz, P. Lennert, F. Lamarche, Gareth J. Barker, R. J. Hemingway, A. Dieckmann, D. Hochman, R. J. Homer, R. Mir, N. J. Thackray, H. Oh, Shlomit Tarem, J. E. Pilcher, S. A. Robins, S. Schreiber, H. Mes, I. P. Duerdoth, R. W. L. Jones, P. A. Elcombe, J. D. Hobbs, G. G. Hanson, S. Rossberg, C. J. Oram, P. E.L. Clarke, P. Jovanovic, Tohru Takeshita, T. Behnke, T. J. McMahon, Austin Ball, C. Moisan, J. P. Walker, R. P. Middleton, D. Menszner, D. L. Rees, J. Becker, M. J. Oreglia, P. Le Du, H. Kreutzmann, Georges Azuelos, P. S. Wells, P. Teixeira-Dias, Alessandro Montanari, C. J. Virtue, J. Schwiening, R. F. McGowan, K. J. Anderson, M. Hauschild, G. J. VanDalen, S. Wotton, Terry Richard Wyatt, R. K. Carnegie, D. E. Klem, M. Coupland, J. R. Carter, N. K. Watson, K. W. Bell, P. Paschievici, G. N. Patrick, M. F. Turner, H. Przysiezniak, R. Yaari, S. Bethke, Max Weber, J. D. Gillies, Marco Cuffiani, J. C. Hill, M. Weymann, Misao Sasaki, J. A. Wilson, Gideon Bella, J. M. Lorah, G. Duckeck, P R Poffenberger, T. Mouthuy, R. J. Barlow, Gideon Alexander, D. J. Miller, H. J. Burckhart, W. Mohr, Jacqueline Batley, Paolo Capiluppi, W. Schappert, H. E. Stier, O. Schaile, L. Janissen, D. Strom, P. G. Estabrooks, J. von Krogh, J. Hart, R. K. Keeler, A. M. Rossi, G. T. Zorn, P. Ashton, Dave Robinson, T. Tsukamoto, S. Levegrün, H. M. Bosch, N. I. Geddes, P. M. Watkins, B. Poli, Wolfram Dietrich Zeuner, O. Runolfsson, Y. Yang, I. Wingerter, L. Lessard, J. Banks, D. Axen, A. Jawahery, G. Tysarczyk-Niemeyer, Claudio Grandi, Peter Sherwood, R. W. Springer, J. Ludwig, K. Runge, P. Bock, P. F. Harrison, P. W. Jeffreys, S. Weisz, R. D. Heuer, A. M. Lee, Stephen Lloyd, Fabrizio Fabbri, D. Van den plas, R. Van Kooten, M. H. Lehto, N. Wermes, S. Bougerolle, W. J. Collins, G. D. Lafferty, T. W. Pritchard, Ehud Duchovni, R. Shypit, A. D. Schaile, Andris Skuja, V. H. Winterer, S. R. Hou, S. J. Pawley, Claus Kleinwort, L. Köpke, H. Ihssen, Tetsuro Mashimo, S. W. Gensler, C. Fukunaga, T. Kobayashi, W. Gorn, G. A. Bahan, G. Giacomelli, B. B. Brabson, E.J. Prebys, D. G. Fong, P. Schenk, J. Gascon, H. von der Schmitt, Frans Meijers, J. L. Pinfold, Marcello Mannelli, M. Jobes, U. Binder, P. Scharff-Hansen, W. J. Larson, J. G. Layter, J. W. Gary, D. Karlen, A. M. Smith, C. M. Hawkes, M. Cooper, Daniel Lellouch, Takehiko Mori, G. Vasseur, B. Lorazo, D. E. Plane, S. Sanghera, Stephen Hillier, G. M. Dallavalle, D. J.P. Dumas, W. R. Gibson, C. Ho, A. Beck, E. Heflin, R. M. Brown, Lorne Levinson, B. W. Kennedy, T. J. Smith, P. Mättig, B. Holl, I. Zacharov, Horst Breuker, J. Mildenberger, Harold Nguyen, Gunter Quast, M. S. Dixit, Paul Kyberd, F. K. Loebinger, Margret Fincke-Keeler, A. Astbury, M. W. Redmond, A. Rollnik, O. Ganel, A. J. Martin, K. Riles, M. Jimack, John Allison, G. Eckerlin, C. K. Hargrove, P. Pfister, R. G. Kellogg, Stefano Marcellini, J. C. Armitage, M. W. Moss, P. M. Hattersley, D. C. Imrie, G. P. Siroli, Kiyotomo Kawagoe, A. P. Wagner, J. M. Roney, B. C. Shen, and K. Stephens
Subjects: Quantum chromodynamics, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Meson, Electron–positron annihilation, High Energy Physics::Phenomenology, Hadron, Nuclear physics, Momentum, High Energy Physics::Experiment, Center of mass, Event (particle physics), Particle Physics - Experiment
Abstract: The production of K0 mesons in e+e− interactions at center of mass energies in the region of the Z0 mass has been investigated with the OPAL detector at LEP. The rate is found to be 2.10±0.02±0.14 K 0 , Z 0 per hadronic event. The predictions from the JETSET and HERWIG generators agree very well with both the rate and the scale invariant cross section (1/σhadβ) (dσ/dxE) for K0 production. Comparisons of the inclusive momentum spectrum with predictions of an analytical QCD formula and with data from lower center of mass energies are presented.
Published: 1991

41. A measurement of photon radiation in lepton pair events from Z0 decays

Author: G. G. Hanson, G. Beaudoin, S. Schreiber, G. Giacomelli, T. J. McMahon, E.J. Prebys, G. Vasseur, J. Schwiening, R. K. Carnegie, M. S. Dixit, Frans Meijers, Shlomo Dado, J. P. Pansart, J. A. Wilson, H. E. Stier, C. Wahl, W. Schappert, B. C. Shen, X. C. Lou, P. G. Estabrooks, J. Mildenberger, Harold Nguyen, N. I. Geddes, C. P. Howarth, W. J. Collins, O. Runolfsson, G. Eckerlin, Giora Mikenberg, W. G. Scott, J. E. Pilcher, L. Lessard, B. Boden, G. D. Lafferty, H. O. Ogren, Christoph Geich-Gimbel, H. Takeda, J. P. Martin, P. M. Watkins, B. Poli, R. Kowalewski, Claudio Grandi, N. C. Wood, Paul Kyberd, F. K. Loebinger, C. M. Hawkes, D. Axen, M. W. Redmond, A. Rollnik, M. Jimack, M. Cooper, Daniel Lellouch, F. G. Oakham, John Hill, S. De Jong, John Allison, P. Igo-Kemenes, T. W. Pritchard, R. G. Kellogg, J. von Krogh, M. M. Deninno, P. E.L. Clarke, T. Mouthuy, M. J. Losty, M. Yurko, Stefano Marcellini, I. Wingerter, Takehiko Mori, P. W. Jeffreys, James Letts, F. Lamarche, P. Singh, R. J. Hemingway, R. Mir, A. M. Lee, H. Oh, G. A. Snow, C. P. Ward, P. Ashton, G. Maringer, H. Jeremie, B. P. O'Neill, Dave Robinson, J. Kroll, O. Schaile, Silvia Arcelli, L. A. del Pozo, P. Jovanovic, R. E. Hughes-Jones, Austin Ball, U. Maur, R. W. L. Jones, A. M. Rossi, D. Menszner, J. E. Conboy, M. Ogg, Michael Dittmar, D. A. Hinshaw, A. K. Honma, T. Tsukamoto, S. Levegrün, Tohru Takeshita, G. Yekutieli, D. Pitman, P. Debu, Alessandro Montanari, P. Le Du, J. G. Layter, A. Pouladdej, H. Kreutzmann, B. Panzer-Steindel, D. C. Imrie, R. Yaari, S. Bethke, S. W. O'Neale, Marco Cuffiani, I. J. Bloodworth, Georges Azuelos, H. M. Fischer, J. F. Kral, K. W. Bell, A. A. Carter, M. J. Oreglia, S. Wotton, A. Michelini, P. Pfister, Gideon Bella, Max Weber, A. D. Schaile, A. C. Janissen, K. J. Anderson, J. Goldberg, M. Weymann, Misao Sasaki, M. Hauschild, J. D. Gillies, C. J. Oram, H. J. Burckhart, Jacqueline Batley, Peter R Hobson, G. P. Siroli, S. A. Robins, S. Sanghera, J. R. Carter, A. Gaidot, R. J. Barlow, P. Paschievici, H. Przysiezniak, M. Settles, V. H. Winterer, K. Stephens, G. N. Patrick, J. R. McNutt, S. Bougerolle, A. Simon, Otmar Biebel, T. Behnke, M. F. Turner, Sachio Komamiya, John Hobbs, D. G. Charlton, E. Ros, F. S. Merritt, S. R. Hou, M. Couch, B. Nellen, P. Leblanc, D. Karlen, R. Humbert, G. Duckeck, R. Ströhmer, B. Holl, T. P. Kokott, Rene Brun, C. Moisan, J. P. Walker, V. Gibson, C. Fukunaga, T. J. Smith, P. Teixeira-Dias, T. Kawamoto, Richard Keeler, D. Strom, J. A. McKenna, M. W. Moss, P. Mättig, A. Astbury, P. M. Hattersley, S. Orito, I. Zacharov, G. Quast, John Baines, G. T. Zorn, M. J. Goodrick, J. L. Pinfold, Horst Breuker, Kiyotomo Kawagoe, R. F. McGowan, I. Cohen, P. Schenk, C. Y. Chang, H. M. Bosch, F. X. Gentit, J. M. Roney, M. Fincke-Keeler, P. Taras, P. Weber, Mitsuaki Nozaki, Wolfram Dietrich Zeuner, D. R. Ward, G. Transtromer, M. Hansroul, O. Ganel, N. K. Watson, A. J. Martin, Erez Etzion, Gareth J. Barker, Claude Leroy, K. Riles, Shlomit Tarem, R. J. Homer, D. J. Miller, C. K. Hargrove, S. Rossberg, A. Jawahery, P. S. Wells, C. J. Virtue, F. Odorici, R. Shypit, Terry Richard Wyatt, D. Hochman, N. J. Thackray, G. Tysarczyk-Niemeyer, R. P. Middleton, M. Coupland, F. C. Grant, M. A. Whalley, Peter Sherwood, R. J. Sobie, R. W. Springer, Alexander Wagner, A. Buijs, J. Hagemann, J. Ludwig, K. Runge, P. Bock, H. Mes, I. P. Duerdoth, D. E. Klem, M. Jobes, U. Binder, P. Scharff-Hansen, G. W. Wilson, J. Hart, W. J. Larson, Y. Yang, P. F. Harrison, P. D. Acton, Stephen Lloyd, P. Poffenberger, A. M. Smith, N. Wermes, B. Lorazo, Ehud Duchovni, H. Ihssen, B. B. Brabson, D. G. Fong, J. Gascon, H. von der Schmitt, S. W. Gensler, T. Kobayashi, J. W. Gary, Marcello Mannelli, Andris Skuja, Phillip Allport, Tetsuro Mashimo, W. Gorn, Gideon Alexander, G. A. Bahan, Paolo Capiluppi, R. Van Kooten, M. H. Lehto, M. Rosvick, S. J. Pawley, P. Berlich, Claus Kleinwort, D. E. Plane, L. Köpke, Stephen Hillier, G. M. Dallavalle, D. R. Rust, Alan Watson, D. J.P. Dumas, P. Lennert, W. R. Gibson, C. Ho, J. Banks, A. Beck, S. Weisz, R. D. Heuer, E. Heflin, Fabrizio Fabbri, D. Van den plas, R. M. Brown, Lorne Levinson, B. W. Kennedy, M. Kuwano, M. Sproston, P. Routenburg, A. Dieckmann, J. M. Lorah, W. Mohr, P. A. Elcombe, D. L. Rees, J. Becker, and G. J. VanDalen
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Photon, Annihilation, Luminosity (scattering theory), Branching fraction, OPAL detector, Resonance (particle physics), Topological definitions, Nuclear physics, Momentum, Lepton pair identification, Selection efficiency, Radiative transfer, High Energy Physics::Experiment, Particle Physics - Experiment, Lepton
Abstract: We have measured the photon yield in lepton pair events recorded by the OPAL detector in a data sample corresponding to an integrated luminosity of 7.1 pb−1 at centre-of-mass energies between 88 GeV and 94 GeV. The results are compared to QED expectations for initial and final state photon radiation. No anomalous photon yield has been found, and stringent limits on the branching ratio for exotic radiative three body Z0 decays into a photon and a pair of leptons are obtained. We also place limits on possible Z0 decays into a photon and a resonance X with subsequent decays of X into a pair of leptons. Acollinear μ+μ− events with missing momentum along the beam direction are identified as events with hard initial state photon radiation and used to measure an average cross section of 15 ±86 pb for e+e− annihilation into μ+μ−, in the so far untested range of centre-of-mass energies between 60 GeV and 84 GeV. This value is consistent with a cross section of 24 pb, expected from Z0 and photon exchange.
Published: 1991

42. A direct observation of quark-gluon jet differences at LEP

Author: H. E. Stier, P. G. Estabrooks, I. J. Bloodworth, P. M. Watkins, S. W. O'Neale, Peter R Hobson, N. K. Watson, M. Settles, Sachio Komamiya, T. P. Kokott, Rene Brun, R. W. L. Jones, R. Mir, H. O. Ogren, H. Oh, I. Wingerter, G. W. Wilson, A. H. Ball, Silvia Arcelli, P. Igo-Kemenes, G. Maringer, D. Karlen, P. Le Du, H. Kreutzmann, B. Panzer-Steindel, G. Giacomelli, H. Jeremie, R. E. Hughes-Jones, U. Maur, M. M. Deninno, J. Kroll, Gideon Bella, F. X. Gentit, M. J. Oreglia, C. Geich-Gimbel, H. J. Burckhart, Jacqueline Batley, J. E. Conboy, M. Ogg, S. Wotton, B. P. O'Neill, F. Lamarche, A. Pouladdej, P. E.L. Clarke, T. Behnke, J. G. Layter, M. Weymann, J. Hagemann, R. J. Hemingway, F. S. Merritt, J. R. Carter, G. N. Patrick, G. Duckeck, P. Jovanovic, A. Simon, Otmar Biebel, D. Strom, J. M. Lorah, S. Sanghera, W. Mohr, G. T. Zorn, D. Menszner, D. G. Charlton, G. Beaudoin, M. Couch, H. M. Bosch, Wolfram Dietrich Zeuner, Alessandro Montanari, R. Humbert, P. Pfister, R. Yaari, J. P. Martin, Shlomo Dado, R. F. McGowan, J. T.M. Chrin, S. Bethke, Marco Cuffiani, John Hill, D. E. Plane, E. K. U. Gross, A. Gaidot, S. De Jong, Stephen Hillier, M. Kuwano, T. Kawamoto, J. C. Armitage, M. Sproston, J. Hart, P. Routenburg, G. M. Dallavalle, X. C. Lou, P. G. Murphy, Erez Etzion, A. Dieckmann, H. Takeda, P. Debu, P. A. Elcombe, S. Orito, John H. Schwarz, Shlomit Tarem, C. Milstene, C. M. Hawkes, Y. Yang, Alan Watson, D. J.P. Dumas, F. G. Oakham, Giora Mikenberg, S. Rossberg, M. Cooper, Daniel Lellouch, J. D. Hobbs, M. Hansroul, D. A. Hinshaw, R. Shypit, Takehiko Mori, P. F. Harrison, R. P. Middleton, D. L. Rees, J. Becker, B. Holl, G. G. Hanson, H. Przysiezniak, J. Goldberg, N. C. Wood, J. D. Gillies, Stephen Lloyd, G. J. VanDalen, S. Bougerolle, W. J. Collins, P. Leblanc, P. W. Jeffreys, I. Zacharov, E.J. Prebys, G. D. Lafferty, R. J. Homer, F. Odorici, A. M. Lee, J. von Krogh, R. J. Barlow, D. Axen, Horst Breuker, M. S. Dixit, M. J. Goodrick, I. Cohen, A. Jawahery, G. Tysarczyk-Niemeyer, Frans Meijers, Peter Sherwood, P. Ashton, Dave Robinson, C. Moisan, J. P. Walker, T. W. Pritchard, P. Teixeira-Dias, G. A. Snow, C. P. Ward, R. W. Springer, J. Ludwig, K. Runge, P. Bock, Michael Dittmar, G. Yekutieli, A. Astbury, A. A. Carter, W. R. Gibson, C. Y. Chang, D. Hochman, N. J. Thackray, C. Ho, C. Fukunaga, O. Ganel, R. Van Kooten, P. Taras, A. Beck, E. Heflin, O. Runolfsson, D. C. Imrie, A. J. Martin, Mitsuaki Nozaki, R. M. Brown, S. Schreiber, L. Lessard, G. J. Barker, Lorne Levinson, B. W. Kennedy, T. J. McMahon, R. K. Carnegie, H. Mes, N. Wermes, D. E. Klem, Claudio Grandi, G. P. Siroli, Ehud Duchovni, J. A. Wilson, I. P. Duerdoth, M. Fincke-Keeler, K. Riles, M. H. Lehto, T. J. Smith, W. Schappert, Paul Kyberd, F. K. Loebinger, J. L. Pinfold, K. Stephens, M. F. Turner, J. R. McNutt, M. W. Redmond, H. Ihssen, A. Rollnik, V. Gibson, John Baines, C. K. Hargrove, P. Schenk, A. D. Schaile, R. Sobie, C. J. Oram, M. Jimack, P. Mättig, D. R. Ward, John Allison, Kiyotomo Kawagoe, L. Janissen, S. W. Gensler, A. P. Wagner, T. Kobayashi, R. G. Kellogg, S. J. Pawley, V. H. Winterer, Gunter Quast, J. M. Roney, Stefano Marcellini, T. R. Wyatt, S. R. Hou, Claus Kleinwort, L. Köpke, Tohru Takeshita, J. Mildenberger, Harold Nguyen, J. Banks, Phillip Allport, G. Eckerlin, S. Weisz, R. D. Heuer, Georges Azuelos, Fabrizio Fabbri, D. Van den plas, K. W. Bell, Richard Keeler, Max Weber, Misao Sasaki, D. R. Rust, B. C. Shen, M. W. Moss, Gideon Alexander, W. G. Scott, P. Lennert, K. J. Anderson, P. M. Hattersley, R. Kowalewski, M. J. Losty, Claude Leroy, J. P. Pansart, O. Schaile, M. Hauschild, P. Paschievici, P R Poffenberger, C. Wahl, B. Nellen, C. P. Howarth, J. E. Pilcher, B. B. Brabson, J. Gascon, H. von der Schmitt, Marcello Mannelli, Andris Skuja, D. J. Miller, Tetsuro Mashimo, B. Poli, W. Gorn, G. A. Bahan, M. Jobes, U. Binder, P. Scharff-Hansen, W. J. Larson, J. W. Gary, A. M. Smith, G. Vasseur, B. Lorazo, N. I. Geddes, P. S. Wells, C. J. Virtue, H. M. Fischer, A. Michelini, S. A. Robins, T. Mouthuy, A. M. Rossi, T. Tsukamoto, S. Levegrün, M. Coupland, M. A. Whalley, Paolo Capiluppi, A. Buijs, and D. G. Fong
Subjects: Physics, Quark, Quantum chromodynamics, Nuclear and High Energy Physics, Top quark, Particle physics, High Energy Physics::Lattice, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, High Energy Physics::Phenomenology, Bottom quark, Photon structure function, Gluon, Nuclear physics, Quark star, High Energy Physics::Experiment, Particle Physics - Experiment, Lepton
Abstract: This is the post-print version of the Article - Copyright @ 1991 Elsevier. Quark and gluon jets in e+e− three-jet events at LEP are identified using lepton tagging of quark jets, through observation of semi-leptonic charm and bottom quark decays. Events with a symmetry under transposition of the energies and directions of a quark and gluon jet are selected: these quark and gluon jets have essentially the same energy and event environment and as a consequence their properties can be compared directly. The energy of the jets which are studied is about 24.5 GeV. In the cores of the jets, gluon jets are found to yield a softer particle energy spectrum than quark jets. Gluon jets are observed to be broader than quark jets, as seen from the shape of their particle momentum spectra both in and out of the three-jet event plane. The greater width of gluon jets relative to quark jets is also visible from the shapes of their multiplicity distributions. Little difference is observed, however, between the mean value of particle multiplicity for the two jet types. This study was supported by the Department of Energy, USA, National Science Foundation, USA, Science and Engineering Research Council, UK, Natural Sciences and Engineering Research Council, Canada, Israeli Ministry of Science, Minerva Gesellschaft, The Japanese Ministry of Education, Science and Culture (the Monbusho) and a grant under the Monbusho International Science Research Program, American Israeli Bi-national Science Foundation, Direction des Sciences de la Mati6re du Commissariat l'Energie Atomique, France, Bundesministerium for Forschung und Technologie, FRG, and the A.P. Sloan Foundation.
Published: 1991

43. The OPAL detector at LEP

Author: P. Igo-Kemenes, G. Maringer, H. Jeremie, N. K. Watson, G. J. VanDalen, P. Vande Vyvre, Eilam Gross, G. T. Zorn, R. E. Hughes-Jones, U. Maur, P. Farthouat, Horst Breuker, P von Walker, Y. Totsuka, R.M. Matson, B Cornet, D. Karlen, S Yamada, S. Zylberajch, R.J. Staley, J. R. Batley, J. Goldberg, P. S. Hinde, B. Nellen, M. Sproston, R. W. Springer, Andris Skuja, A. M. Rossi, J. Zimmer, K Ahmet, A. Buijs, H C Weber, D. M. Strom, M Lamblin, James M. Hill, E. Neuheimer, L. Godfrey, Tohru Takeshita, P. Routenburg, T. Tsukamoto, A. Dieckmann, M Fillion, Tetsuro Mashimo, H. M. Fischer, Sergo, A. Michelini, D Micolon, Tatsuo Kawamoto, O. Schaile, T. Behnke, P. Leblanc, H. Hartmann, I. P. Duerdoth, A Therond, S Jaroslawski, J. R. Carter, R. Yaari, B Gaillard-Grenadier, D. C. Colley, Georges Azuelos, M Marquet, A. Shapira, A. J.P. O'Dowd, E. Mauer, Shlomo Dado, J. M. Roney, E Poli, O. Ganel, N. Zwang, M. J. Goodrick, Joachim Heintze, I. Cohen, A. H. Ball, Aharon Levy, K. W. Bell, N. I. Geddes, H Gao, J. Banks, J. M. Lorah, M. Jimack, John Allison, W. Gorn, L. Mazzone, M. S. Dixit, D. Duchesneau, Frans Meijers, H Wenninger, P Rada, R. Rusniak, Makoto Minowa, W. Mohr, J. C. Hill, K. Riles, P. G. Murphy, S. Schreiber, Gibson, S. Weisz, R L Amstrong, G Canova, J.A. Lidbury, T. Zawistowski, John Hart, G.L. Giles, Gideon Bella, A Penton, T. Kobayashi, Stephen Lloyd, Fabrizio Fabbri, M. Jobes, J.L. Chevalley, M. W. Moss, D. Van den plas, M.M.B. Lasota, G. Duckeck, K. Stephens, M. Weymann, W. R. Gibson, Robert M Brown, R Losserand-Madoux, M. Uldry, P. M. Hattersley, G. Linser, B. C. Shen, John Hobbs, P. Scharff-Hansen, C. K. Hargrove, G. Mikenberg, J. D. Gillies, H. Matsumura, M Z Akraway, T. J. McMahon, R. G. Kellogg, M. Imori, R. Kolpin, D. J. Miller, O. W. Davies, L Baisin, Mark Oreglia, B. P. O'Neill, F.F. Heymann, H. J. Burckhart, J. E. Conboy, M. M. Deninno, M Morpurgo, Ehud Duchovni, W. J. Larson, D. Granite, B. Gandois, B G Duff, G.T.J. Arnison, H. Wang, J. W. Gary, L Briot, P Giudici, R Payne, U Seidler, Kiyotomo Kawagoe, N. C. Wood, R. A. Sansum, Stefano Marcellini, R. Kowalewski, Peter R Hobson, B. Parkinson, Y Gal, J. Waterhouse, W. J. Murray, Gunter Quast, A. M. Smith, C. M. Roach, C. M. Hawkes, A. P. Wagner, K H Souten, G Artusi, H. von der Schmitt, L. Denton, Kelby Anderson, S. Gross, M. J. Losty, F. X. Gentit, B. Lorazo, A Lefrancois, P Gorce, G. Bavaria, R. K. Carnegie, A L Fletcher, Masatoshi Koshiba, C. P. Ward, A Beer, D. J. White, G. Knop, L Biffoni, John Baines, B. J. Saunders, S. W. Gensler, M. Coupland, P Kobe, P. M. Watkins, D Lascols, J. Armitage, F Bourgeois, F Rochner, D. L. Rees, D Rybkowski, P.R. Goldey, M. Regimbald, Harold Nguyen, S. J. Hillier, K. Karner, C. J. Virtue, James Pinfold, B Vuillerme, I. Wingerter, F Pouyat, J. Gascon, T. P. Kokott, Rene Brun, J. A. Wilson, M.D. Jeffs, Chikara Fukunaga, H. J. Meyer, P. Wicht, D. C. Imrie, K Scheuring, M D Rousseau, K Miels, W.W. Miller, W. Glessing, R. P. Middleton, G Schmidlin, Phillip Allport, M. F. Turner, D. R. Ward, F L Desrosier, S. J. Pawley, Claus Kleinwort, L. Köpke, A. Weltin, G. N. Patrick, B. Wünsch, A. C. McPherson, Lorne Levinson, P E Estabrooks, G. P. Siroli, A. Simon, R. Bard, R J Shaw, George Lafferty, I. D'Antone, Norbert Wermes, M. Hansroul, Marcello Mannelli, C. N. P. Gee, Mitsuaki Nozaki, J. Ma, G. J. Barker, W M Evans, W. Schappert, A Eyting, F. K. Loebinger, C. Milstène, Otmar Biebel, J.F. Connolly, M. Couch, M Grossi, F. Lamarche, L. Lessard, M Mast, P. W. Jeffreys, M. Webel, J. Grunhaus, D. Joos, B. W. Kennedy, Britt Anderson, R. Cranfield, R. Humbert, P. Lennert, R. J. Homer, Allen Mincer, M. W. Redmond, J O Peterson, Peter Sherwood, James Pilcher, R Lorenzi, A Renoux, A. A. Macbeth, G. W. Wilson, Gideon Alexander, N. Lupu, Paolo Capiluppi, G Gagnon, A. Rollnik, K. Zankel, D M Sendall, Roger Barlow, D. Hochman, J. T.M. Chrin, M. Hauschild, F Verkerk, S. A. Wotton, R. Milborrow, R. J. Hemingway, P. Jovanovic, H. P. Borner, G Prodon, D. Menszner, Achim Müller, G. M. Dallavalle, P Keyberd, M. Beaulieu, F. S. Merritt, Alessandro Montanari, S. W. O'Neale, W N Stokes, C. Wahl, R Stephenson, H. Yamashita, S. Orito, John H. Schwarz, C. P. Howarth, M Lautscham, A Duperloup, A Charalambous, A. Possoz, H. Takeda, R. D. Heuer, M Cyvoct, F. G. Oakham, B Langset, T. W. Pritchard, L Marradi, D. E. Plane, C. Y. Chang, D. Hatzifotiadou, J. Raab, M. Shoa, O. Runolfsson, Alan Watson, F Massera, D. J.P. Dumas, R Shally, M Ferrari, Dave Charlton, R. W. L. Jones, P. Ashton, E. J. Spreadbury, P. Le Du, A. D. Schaile, H. Kreutzmann, P. Rapp, E. Jin, G. Giacomelli, H. Sanders, T. R. Wyatt, S. R. Hou, Michael Dittmar, G. Yekutieli, A. A. Carter, J.D. Colmer, J. Hagemann, J. Ludwig, T Goiffon, K. Runge, P. Bock, E. E. Elsen, H. Mes, P. Steinberg, J. Kroll, G. Crone, A Sato, M Guillot, H. M. Bosch, Wolfram Dietrich Zeuner, F. Beck, T. J. Smith, P. Mättig, I. J. Bloodworth, D. Voillat, Daniel Lellouch, S A Clark, S Tuffanelli, D. E. Klem, G Pozzo, J. G. Layter, P.S. Rozmarynowski, M Chamot, C. Beard, W. Seidl, R. G. Glasser, J. P. Martin, R. Hammarström, G. Tysarczyk, M. T. French, J. Thiebes, B. Holl, and H El-Mamouni
Subjects: Physics, Nuclear and High Energy Physics, Calorimeter (particle physics), Detector, Hadron, Solenoid, Tracking (particle physics), Nuclear physics, Lead glass, visual_art, visual_art.visual_art_medium, Detectors and Experimental Techniques, Instrumentation, Muon detector
Published: 1990

44. A direct search for new charged heavy-leptons at LEP

Author: S. Schreiber, T. J. McMahon, B. C. Shen, R. K. Carnegie, J. M. Lorah, Makoto Minowa, W. Mohr, Kiyotomo Kawagoe, J. A. Wilson, Masatoshi Koshiba, K. Stephens, F. Lamarche, R. J. Hemingway, Harold Nguyen, Mark Oreglia, D. J. Miller, P. Jovanovic, Austin Ball, F. S. Merritt, I. J. Bloddworth, D. Menszner, H. Yamashita, M. Z. Akrawy, Alessandro Montanari, A. Possoz, W. Schappert, C. J. Virtue, H. Takeda, A. P. Wagner, M. T. French, R. Kowalewski, J. M. Roney, C. M. Roach, R. Ströhmer, D. Strom, G. Knop, M. Coupland, J. D. Gillies, A. A. Macbeth, G. W. Wilson, M. Hauschild, G. T. Zorn, N. C. Wood, John Baines, A. Simon, R. J. Barlow, D. Granite, E. K. U. Gross, P. Igo-Kemenes, G. Maringer, H. Jeremie, M. Regimbald, O. Ganel, Wolfram Dietrich Zeuner, F. Beck, Otmar Biebel, R. W. L. Jones, M. Sproston, P. Routenburg, D. G. Charlton, Michael Dittmar, D. Karlen, R. E. Hughes-Jones, U. Maur, Achim Müller, J. Ma, D. R. Ward, G. Yekutieli, K. Riles, F. K. Loebinger, A. Dieckmann, M. Couch, Phillip Allport, F. G. Oakham, P. Le Du, D. Duchesneau, M. M.B. Lasota, O. W. Davies, J. Grunhaus, P. A. Elcombe, S. Wotton, H. Kreutzmann, A. A. Carter, D. E. Plane, Stephen Hillier, E. Jin, A. Michellini, C. Milstene, P. W. Jeffreys, T. J. Smith, B. Holl, G. Giacomelli, J. C. Armitage, A. M. Rossi, M. W. Redmond, D. L. Rees, R. Yaari, J. T.M. Chrin, H. Mes, Gideon Bella, P. Mättig, T. Tsukamoto, H. J. Burckhart, B. Wuensch, G. J. VanDalen, Jacqueline Batley, H. Hagedorn, A. C. McPherson, S. Bethke, Marco Cuffiani, A. Shapira, H. El Mamouni, Tohru Takeshita, A. Rollnik, P. Farthouat, Horst Breuker, Christoph Geich-Gimbel, C. M. Hawkes, Daniel Lellouch, G.T.J. Arnison, J. Goldberg, A. Buijs, T. Kawamoto, Takehiko Mori, S. Zylberajch, Gideon Alexander, P. S. Hinde, G. A. Snow, C. P. Ward, D. Hochman, Norbert Wermes, Alan Watson, D. J.P. Dumas, M. M. Deninno, J. Kroll, P. Kyberd, Paolo Capiluppi, H. E. Stier, M. W. Moss, A. Jawahery, I. P. Duerdoth, F. Odorici, M. Weymann, Georges Azuelos, S. Orito, C. Wahl, C. P. Howarth, P. G. Estabrooks, F. X. Gentit, G. Bavaria, P. M. Hattersley, H. Wang, W. R. Gibson, J. E. Pilcher, Peter Sherwood, R. W. Springer, John H. Schwarz, Gunter Quast, N. K. Watson, K. W. Bell, J. E. Conboy, C. K. Hargrove, C. Ho, N. I. Geddes, M. Ogg, J. Ludwig, K. Runge, P. Bock, H. Oh, Ehud Duchovni, P. M. Watkins, John Allison, Max Weber, M. Hansroul, E. Heflin, D. C. Imrie, Misao Sasaki, G. M. Dallavalle, Shlomo Dado, J. D. Hobbs, R. M. Brown, Lorne Levinson, R. A. Sansum, G. P. Siroli, B. Nellen, B. Poli, B. W. Kennedy, P. G. Murphy, O. Runolfsson, K. J. Anderson, A. Pouladdej, J. von Krogh, I. Wingerter, Giora Mikenberg, L. Lessard, S. W. Gensler, R. G. Kellogg, J. R. Carter, J. Raab, G. N. Patrick, B. Gandois, M. Imori, R. J. Homer, P. Leblanc, T. Kobayashi, S. W. O'Neale, S. J. Pawley, Peter R Hobson, O. Schaile, H. M. Fischer, J. Waterhouse, A. J.P. O'Dowd, P. Ashton, Stefano Marcellini, Claus Kleinwort, L. Köpke, M. J. Losty, T. P. Kokott, Rene Brun, J. Steuerer, J. Hart, C. Y. Chang, Mitsuaki Nozaki, J. Banks, Y. Yang, S. Weisz, R. D. Heuer, Fabrizio Fabbri, M. J. Goodrick, Joachim Heintze, D. Van den plas, Stephen Lloyd, I. Cohen, D. E. Klem, P. Lennert, M. F. Turner, W. J. Murray, B. P. O'Neill, J. Hagemann, Erez Etzion, B. J. Saunders, Gareth J. Barker, R. P. Middleton, M. S. Dixit, Despina Hatzifotiadou, D. G. Fong, G. D. Lafferty, H. von der Schmitt, T. W. Pritchard, F. Roehner, Marcello Mannelli, C. N. P. Gee, Andris Skuja, C. Fukunaga, Tetsuro Mashimo, Frans Meijers, M. Jimack, W. Gorn, J. P. Martin, J. L. Pinfold, John Hill, M. Jobes, E. J. Spreadbury, A. D. Schaile, P. Scharff-Hansen, W. J. Larson, P. Grosse-Wiesmann, J. W. Gary, A. M. Smith, V. H. Winterer, B. Lorazo, T. R. Wyatt, S. R. Hou, G. Tysarczyk, J. G. Layter, and S. Sanghera
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Missing energy, Annihilation, Electron–positron annihilation, High Energy Physics::Phenomenology, Resonance (particle physics), Momentum, Nuclear physics, Massless particle, High Energy Physics::Experiment, Neutrino, Particle Physics - Experiment, Lepton
Abstract: This is the post-print version of the Article - Copyright @ 1990 Elsevier Results are presented from a search for a new charged heavy lepton in e+e− annihilation. The data were taken with the OPAL detector at LEP during a scan of the Z0 resonance. Two independent search techniques were used, one looking for events with large missing energy and missing momentum transverse to the beam, and the other for events with isolated energetic leptons. Two candidate events, consistent with expected background, were found in the first search; none was found in the second. These results allow the exclusion at the 95% confidence level of a charged heavy lepton of mass less than 44.3 GeV/c2 if it is assumed to have a massless neutrino partner. Limits are also presented for the case of a massive neutrino. This study is supported by The Bundesministerium f'tir Forschung und Technologie, FRG, The Department of Energy, USA, The Institut de Recherche Fondamentale du Commissariat a l'Energie Atomique, The Israeli Ministry of Science, The Minerva Gesellschaft, The National Science Foundation, USA, The Natural Sciences and Engineering Research Council, Canada, The Japanese Ministry of Education, Science and Culture (the Monbusho) and a grant under the Monbusho International Science Research Program, The Science and Engineering Research Council, UK and The A.P. Sloan Foundation.
Published: 1990

45. Measuring the chemical composition of cosmic rays at ? 1013?1015 eV by utilizing the solar and geomagnetic fields

Author: J. Spitzer, P. Lennert, Werner Hofmann, Bogdan Povh, S. Polenz, Bernhard Schmidt, W. Brückner, and Joachim Heintze
Subjects: Physics, Ionospheric dynamo region, Earth's magnetic field, Spectrometer, Space and Planetary Science, Coronal mass ejection, Astronomy and Astrophysics, Cosmic ray, Angular resolution, Gamma-ray astronomy, Astrophysics, Magnetic field
Abstract: According to a proposal of Lloyd-Evans (1985), the average charge of particles in the cosmic radiation near 1014eV can be determined by observing the effect of the solar magnetic field on the Sun's shadow in the angular distribution of energetic primary cosmic ray particles. This suggestion is shown to be realizable with a new type of EAS-array proposed for the purpose of high energy γ-ray astronomy. The same measurement provides information on the integrated strength of the solar magnetic field. As the array will be sensitive and provide good angular resolution down to a few times 1012eV, more detailed results on the primary composition near 1013eV can be obtained by investigating the shape of the shadow of the Moon as affected by the geomagnetic field.
Published: 1989

46. Tau-lepton production and decay at Petra energies

Author: R. Felst, K. Stephens, J. A.J. Skard, A. H. Ball, Alexander Finch, D. Schmidt, H. Krehbiel, P. Hill, P. Laurikainen, G. Knies, Stephen Robert Wagner, Hugh McCann, Tohru Takeshita, P. Lennert, J. Spitzer, J. E. Olsson, T. Kobayashi, J. Heintze, J. T.M. Chrin, A. A. Macbeth, K. Kawagoe, Shoichi Yamada, K. Ambrus, T. Kawamoto, Mitsuaki Nozaki, D. Clarke, F. K. Loebinger, B. Naroska, H. Takeda, D. Cords, Gareth Hughes, W. Bartel, P. Warming, J. M. Nye, I. P. Duerdoth, E. Elsen, S. Bethke, A. Petersen, M. Kuhlen, D. Haidt, G. T. Zorn, N. Magnussen, Claus Kleinwort, P. Steffen, G. Dietrich, S. L. Cartwright, A. Dieckmann, John Allison, C. K. Bowdery, G. Weber, G. Heinzelmann, H. Kado, H. Matsumura, T. Greenshaw, F. Foster, L. Becker, U. Schneekloth, H. Rieseberg, Roger Barlow, J. von Krogh, R. Meinke, P. G. Murphy, R. Ramcke, R. Marshall, H. E. Mills, S. Komamiya, R. G. Glasser, K. H. Hellenbrand, Robin Middleton, A. Wagner, and J. Hagemann
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Electron–positron annihilation, media_common.quotation_subject, Electroweak interaction, High Energy Physics::Experiment, Asymmetry, Charged particle, Lepton, media_common
Abstract: The production and decay of τ-pairs was studied with the JADE detector at PETRA at center-of-mass energies of 30 ⩽√s ⩽ 46.78 GeV. The total production cross section for τ-pairs agreed with QED predictions to order α3. Lower limits on QED cut-off parameters of Λ+ > 285 GeV and Λ− > 210 GeV at 95% confidence level were ontained. The decay branching fractions into one and three charged particles were determined to be (86.1 ± 0.5 ± 0.9)% and (13.6±0.5 ±0.80)%. In the angular distributions a forward-backward asymmetry was observed, from which the axial-vector weak charge to the τ was determined to be aτ = −0.74 ± 0.22 in agreement with the standard model. An analysis of the process e+e− → τ+τ−γ showed agreement with QED calculations to O(α3).
Published: 1985

47. A study of photon production in hadronice + e ? annihilation

Author: Alexander Finch, C. K. Bowdery, R. G. Glasser, H. Takeda, E. Elsen, F. K. Loebinger, S. Komamiya, D. Schmidt, B. Sechi-Zorn, J. Spitzer, H. Rieseberg, F. Foster, H. Krehbiel, H. Matsumura, L. Becker, R. Meinke, T. Greenshaw, Stephen Robert Wagner, M. Kuhlen, A. H. Ball, R. Felst, P. Laurikainen, P. Lennert, J. von Krogh, R. Ramcke, R. Marshall, G. Heinzelmann, Tetsuro Mashimo, Tohru Takeshita, J. T.M. Chrin, A. A. Macbeth, G. Knies, H. E. Mills, K. Stephens, K. Ambrus, T. Kawamoto, B. Naroska, J. B. Whittaker, T. Nozaki, T. Kobayashi, G. T. Zorn, P. Hill, Shoichi Yamada, P. G. Murphy, A. Petersen, D. Clarke, G. Weber, J. E. Olsson, John Allison, Claus Kleinwort, D. Haidt, J. Heintze, D. Cords, K. Kawagoe, S. Bethke, S. L. Cartwright, Makoto Minowa, Gareth Hughes, U. Schneekloth, K. H. Hellenbrand, Robin Middleton, H. Junge, Roger Barlow, P. Warming, K. Meier, H. Kado, W. Bartel, A. Dieckmann, J. Hagemann, A. Wagner, I. P. Duerdoth, J. A.J. Skard, J. M. Nye, P. Steffen, and G. Dietrich
Subjects: Physics, Particle physics, Photon, Annihilation, Physics and Astronomy (miscellaneous), Meson, Electron–positron annihilation, Hadron, Elementary particle, Multiplicity (mathematics), Nuclear physics, Pion, High Energy Physics::Experiment, Engineering (miscellaneous)
Abstract: The production of photons ine+e−→γ+hadrons is investigated at three centre of mass energies around 14, 22 and 34 GeV. On average, photons carry 25% of the total available energy, with a multiplicity similar to the charged multiplicity. The inclusive photon spectra are found to scale with the centre of mass energy as a function of the Feynman variablex. π0 and η mesons are reconstructed from their decay photons. The slopes of the spectra are similar to that for charged pions and approximate scaling is observed for π0 production. The mean π0 and η multiplicities are given. The observed photon yield can be fully accounted for by hadron decays and initial state radiation. However, up to one extra photon per event from other sources cannot be excluded.
Published: 1985

48. A search for new heavy leptons at PETRA

Author: J. E. Olsson, J. Heintze, A. H. Ball, K. H. Hellenbrand, H. Matsumura, G. Heinzelmann, E. Elsen, M. Koshiba, R. Eichler, W. Bartel, P. Rowe, K. Stephens, R. Felst, H. Krehbiel, A. Sato, I. P. Duerdoth, G. Bamford, A. A. Macbeth, Hugh McCann, Yosuke Watanabe, F. Foster, P. Steffen, G. Dietrich, John Allison, Y. Totsuka, C. Bowdery, H. Wriedt, H. Takeda, R. Marshall, H. E. Mills, Mitsuaki Nozaki, S. Kawabata, P. Lennert, R. D. Heuer, G. F. Pearce, T. Kobayashi, D. Cords, T. Nozaki, G. Weber, S. Bethke, F. K. Loebinger, S. Odaka, Shoichi Yamada, C. Yanagisawa, A. Petersen, P. Warming, D. Haidt, D. Clarke, Makoto Minowa, A. Wagner, P. G. Murphy, U. Schneekloth, B. Naroska, Karlheinz Meier, H. Rieseberg, Gareth Hughes, H. Kado, A. Bell, J. von Krogh, Roger Barlow, S. Orito, I. Glendinning, L. H. O'Neill, Junichi Kanzaki, M. C. Goddard, and S. Komamiya
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, High Energy Physics::Phenomenology, High Energy Physics::Experiment, Nuclear Experiment, Lepton, Vertex (geometry)
Abstract: Results are presented on a search for new heavy leptons, a sequential heavy lepton L ± , and an electron-type neutral heavy lepton E 0 , using the JADE detector at PETRA. No evidence for either of these particles was observed. A lower mass limit for the L ± is determined to be 18.0 GeV/ c 2 at 95% CL. Lower mass limits for the E 0 are 24.5 GeV/ c 2 and 22.5 GeV/ c 2 , in the case of universal V + A and V − A coupling at the W-e-E vertex, respectively.
Published: 1983

49. A measurement of the η radiative width Γη→γγ

Author: A. Petersen, D. Haidt, S. L. Cartwright, A. H. Ball, K. Stephens, K. H. Hellenbrand, R. G. Glasser, Robin Middleton, Alexander Finch, D. Schmidt, B. Sechi-Zorn, J. B. Whittaker, Shoichi Yamada, F. K. Loebinger, Hugh McCann, J. Spitzer, K. Ambrus, S. Komamiya, I. P. Duerdoth, Tetsuro Mashimo, Gareth Hughes, John Baines, P. Hill, J. M. Nye, D. Cords, T. Kobayashi, J. A.J. Skard, G. Dietrich, J. T.M. Chrin, S. Bethke, T. Kawamoto, Tohru Takeshita, G. T. Zorn, R. Ramcke, R. Marshall, H. E. Mills, G. Heinzelmann, T. Nozaki, G. Weber, R. Felst, J. Hagemann, T. Greenshaw, H. Junge, D. Clarke, K. Meier, M. Kuhlen, John Allison, H. Kado, A. Wagner, H. Krehbiel, C. K. Bowdery, Stephen Robert Wagner, W. Bartel, P. Laurikainen, P. Lennert, B. Naroska, F. Foster, L. Becker, Claus Kleinwort, D. Steffen, Roger Barlow, P. G. Murphy, R. Meinke, E. Elsen, H. Matsumura, Makoto Minowa, U. Schneekloth, A. Dieckmann, H. Takeda, G. Knies, H. Rieseberg, A. A. Macbeth, J. von Krogh, J. E. Olsson, J. Heintze, K. Kawagoe, and P. Warming
Subjects: Nuclear physics, Physics, Particle physics, Nuclear and High Energy Physics, Meson, Radiative transfer, High Energy Physics::Experiment, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Nuclear Experiment, Value (mathematics), Astrophysics::Galaxy Astrophysics
Abstract: The radiative width of the η meson has been measured at PETRA in photon-photon collisions. The resulting value is Γη→γγ=0.53±0.04±0.04 keV.
Published: 1985

50. Exclusive production of proton-antiproton pairs in photon-photon collisions

Author: R. Ramcke, R. Marshall, D. Cords, Alexander Finch, J. Spitzer, G. Heinzelmann, H. Rieseberg, Tohru Takeshita, I. P. Duerdoth, John Allison, C. K. Bowdery, G. T. Zorn, H. E. Mills, H. Takeda, G. Weber, P. Warming, N. Magnussen, P. Laurikainen, Shoichi Yamada, F. Foster, L. Becker, P. Lennert, P. Hill, S. Komamiya, H. Krehbiel, Stephen Robert Wagner, Roger Barlow, H. Matsumura, A. A. Macbeth, A. Dieckmann, J. A.J. Skard, D. Clarke, E. Elsen, R. Meinke, J. T.M. Chrin, J. M. Nye, T. Kawamoto, P. Steffen, G. Dietrich, H. Kado, Gareth Hughes, P. G. Murphy, A. Petersen, K. H. Hellenbrand, D. Haidt, Robin Middleton, R. G. Glasser, S. L. Cartwright, M. Kuhlen, U. Schneekloth, W. Bartel, D. Schmidt, T. Kobayashi, F. K. Loebinger, R. Felst, B. Naroska, G. Knies, K. Stephens, Claus Kleinwort, J. von Krogh, J. E. Olsson, J. Heintze, K. Kawagoe, A. H. Ball, K. Ambrus, T. Greenshaw, J. Hagemann, A. Wagner, and S. Bethke
Subjects: Physics, Nuclear and High Energy Physics, Range (particle radiation), Particle physics, Photon, Proton, JADE (particle detector), Cross section (geometry), Nuclear physics, Antiproton, High Energy Physics::Experiment, Invariant mass, Nuclear Experiment, Nucleon
Abstract: Total and differential cross sections for exclusive production of proton-antiproton pairs in photon-photon collisions have been measured using the JADE detector at PETRA. The total cross section in the CM angular |cos θ∗| < 0.6 reaches a maximum value of 3.8 nb for a γγ invariant mass of Wγγ = 2.25 GeV, and decreases rapidly for higher values of Wγγ. In the range 2.0 GeV < Wγγ < 2.6 GeV the angular distribution is not isotopic. The nucleons are preferentially emitted at large angles to the collision axis.
Published: 1986

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