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1. Multi-photon events with large missing energy in e+e− collisions at s=192–209 GeV

Author

James Pinfold, R. Seuster, P. Scharff-Hansen, A. M. Smith, Andris Skuja, Tetsuro Mashimo, M. F. Turner-Watson, N. Meyer, M. Kupper, Daniel Lellouch, Takehiko Mori, L. Brigliadori, T. Behnke, S. W. O'Neale, P. O. Günther, J. Goldberg, M. Boutemeur, F. S. Merritt, K. J. Anderson, Thorsten Wengler, B. C. Shen, M. Donkers, Yoram Rozen, Siegfried Bethke, J. A. McKenna, Tara Shears, W. G. Scott, S. Yamashita, Junichi Kanzaki, Silvia Arcelli, J. W. Gary, P. Igo-Kemenes, K. Buesser, M. Gruwé, K. Ishii, H. Jeremie, Gideon Bella, Gianni Masetti, C. Y. Chang, R. M. Brown, Lorne Levinson, Christoph Rembser, Christoph Geich-Gimbel, Teresa Barillari, H. J. Burckhart, A. Csilling, S. Moed, Gabriele Benelli, Guenter Duckeck, D. Axen, Dezso Horvath, Erez Etzion, Richard Nisius, Graham Wilson, I. R. Bailey, O. Schaile, Oana Elena Vickey Boeriu, Raimund Ströhmer, Stefan Kluth, T. Kuhl, Shlomit Tarem, P. Mättig, Shoji Asai, Marco Cuffiani, Shlomo Dado, Richard Teuscher, A. J. Martin, F. Spano, M. J. Oreglia, M. Hauschild, M. Giunta, D. Zer-Zion, Robert McPherson, L. Zivkovic, Lutz Feld, D. Toya, P. J. Bell, G. Gaycken, W. Mader, Beatrix Dienes, F. K. Loebinger, C. Pahl, Giora Mikenberg, M. Schumacher, Matthias Schröder, Alexander Oh, J. R. Carter, W. Menges, Otmar Biebel, Paolo Giacomelli, Ivor Fleck, J. Ludwig, K. Runge, P. Bock, Georges Azuelos, T. R. Wyatt, I. Nakamura, D. Lanske, T. R. Junk, A. D. Schaile, Joleen Pater, Edward K. G. Sarkisyan, Gabriella Pasztor, K. Hoffman, E. Tsur, Gregor Herten, C. M. Hawkes, E. A. De Wolf, P. Vannerem, H. Nanjo, T. Schörner-Sadenius, Fabrizio Fabbri, A. Frey, Balazs Ujvari, H. A. Neal, Isabel Marian Trigger, K. W. Bell, A. Gupta, C. F. Vollmer, C. P. Ward, P. Gagnon, A. Harel, J. E. Pilcher, J. C. Hill, George Lafferty, Norbert Wermes, T. Kawamoto, Jochen Schieck, Ikuo Ueda, D. M. Strom, R. J. Barlow, J. Lu, Tobias Kramer, P. Amaral, Satoshi Mihara, S. Söldner-Rembold, Gunter Wolf, S. Orito, Zoltan Laszlo Trocsanyi, Kiyotomo Kawagoe, Gideon Alexander, D. Karlen, Frank Fiedler, B. Poli, R. K. Keeler, Dave Charlton, P. S. Wells, Arnulf Quadt, H. Mes, P. M. Watkins, A. T. Watson, Klaus Rabbertz, I. P. Duerdoth, S. Braibant, P. Renkel, Stephen Lloyd, P. Sherwood, Achim Stahl, Oliver Pooth, Ehud Duchovni, John Allison, D. E. Plane, N. Kanaya, A. Michelini, R. G. Kellogg, M. Hamann, R. D. Heuer, Csaba Hajdu, T. Kobayashi, A. Ludwig, Stefano Marcellini, Claudia Ciocca, James Letts, R. Vértesi, R. J. Sobie, Joost Vossebeld, Klaus Desch, P. Tran, K. Sachs, Philip Bechtle, Gordon H. Hanson, D. R. Ward, M. Ford, N. K. Watson, R. J. Batley, S. Campana, C. Ainsley, J. von Krogh, R. J. Hawkings, J. Dubbert, R. K. Carnegie, J. A. Wilson, M. A. Thomson, E. K. U. Gross, Eric Torrence, D. J. Miller, R. J. Hemingway, J. Lillich, B. W. Kennedy, P. Jovanovic, Peter Krieger, M. Przybycień, H. Landsman, A. A. Carter, E. L. Barberio, M. Verzocchi, P. F. Åkesson, Giovanni Abbiendi, J. M. Roney, M. Tasevsky, Koichi Nagai, W. Mohr, J. Grunhaus, A. Mutter, Sachio Komamiya, K. Kruger, T. Saeki, J. G. Layter, Alain Bellerive, G. Anagnostou, H. Voss, G. Giacomelli, Pamela Ferrari, A. De Roeck, M. Kobel, and Frans Meijers

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Missing energy, 010308 nuclear & particles physics, Electron–positron annihilation, 01 natural sciences, 7. Clean energy, Nuclear physics, Massless particle, Pair production, Excited state, 0103 physical sciences, Neutralino, Gravitino, 010306 general physics, Bhabha scattering
Abstract

Events with a final state consisting of two or more photons and large missing transverse energy have been observed in e + e − collisions at centre-of-mass energies in the range 192–209 GeV using the OPAL detector at LEP. Cross-section measurements are performed within the kinematic acceptance of the selection and compared with the expectations from the Standard Model process e + e − → ν ν ¯ γ γ ( γ ) . No evidence for new physics contributions to this final state is observed. Upper limits on σ ( e + e − → X X ) ⋅ BR 2 ( X → Y γ ) are derived for the case of stable and invisible Y. In the case of massive Y the combined limits obtained from all the data range from 10 to 60 fb, while for the special case of massless Y the range is 20 to 40 fb. The limits apply to pair production of excited neutrinos ( X = ν * , Y = ν ), to neutralino production ( X = χ ˜ 2 0 , Y = χ ˜ 1 0 ) and to supersymmetric models in which X = χ ˜ 1 0 and Y = G ˜ is a light gravitino.

Published
2004
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2. Flavour independent search for Higgs bosons decaying into hadronic final states in e+e− collisions at LEP

Author

Silvia Arcelli, N. Kanaya, Daniel Lellouch, Erez Etzion, Gordon H. Hanson, M. Ford, Takehiko Mori, A. Okpara, Stefan Kluth, Shlomit Tarem, T. R. Junk, Christoph Geich-Gimbel, Gregor Herten, R. M. Brown, Lorne Levinson, J. Böhme, M. Giunta, Gianni Masetti, C. Y. Chang, Alexander Oh, C. Pahl, T. Behnke, A. J. Martin, Georges Azuelos, E. Tsur, C. M. Hawkes, J. Goldberg, A. Hocker, S. Moed, G. D. Lafferty, S. Yamashita, E. K. U. Gross, I. R. Bailey, Gideon Bella, H. J. Burckhart, I. Nakamura, D. Lanske, D. R. Ward, K. Hoffman, H. Mes, P. Igo-Kemenes, A. Mutter, J. E. Pilcher, A. D. Schaile, Isabel Marian Trigger, K. W. Bell, M. A. Thomson, Robert McPherson, Gabriella Pasztor, P. Vannerem, Fabrizio Fabbri, A. Frey, Raimund Ströhmer, R. J. Hemingway, I. P. Duerdoth, M. Gruwé, K. Ishii, H. Jeremie, P. Gagnon, S. Braibant, James Pinfold, D. Zer-Zion, W. Mader, J. C. Hill, Lutz Feld, B. W. Kennedy, F. K. Loebinger, J. Lillich, A. Harel, Thorsten Wengler, R. Seuster, Tobias Kramer, Ikuo Ueda, D. M. Strom, D. E. Plane, Klaus Rabbertz, Ivor Fleck, Yoram Rozen, R. K. Keeler, Christoph Rembser, J. M. Roney, M. Boutemeur, F. S. Merritt, J. Lu, Joleen Pater, Edward K. G. Sarkisyan, C. P. Ward, Zoltan Laszlo Trocsanyi, B. Poli, Richard Teuscher, Stephen Lloyd, B. C. Shen, P. Jovanovic, Tara Shears, M. Tasevsky, Beatrix Dienes, Richard Nisius, M. Donkers, P. Tran, O. Schaile, M. Przybycień, A. Klier, R. J. Batley, Balazs Ujvari, H. A. Neal, Arnulf Quadt, Koichi Nagai, W. Mohr, Marco Cuffiani, S. Söldner-Rembold, Gabriele Benelli, Siegfried Bethke, W. G. Scott, Peter Krieger, Junichi Kanzaki, J. W. Gary, P. M. Watkins, T. Kuhl, Paolo Giacomelli, A. A. Carter, Gunter Wolf, N. K. Watson, G. Gaycken, J. A. McKenna, J. Grunhaus, L. Brigliadori, M. Hamann, K. Buesser, M. Schumacher, M. Hauschild, D. Karlen, P. Renkel, Oliver Pooth, C. F. Vollmer, E. A. De Wolf, John Allison, Teresa Barillari, M. Verzocchi, S. W. O'Neale, P. O. Günther, A. Csilling, C. Ainsley, M. J. Oreglia, Dezso Horvath, Stefano Rosati, Jochen Schieck, R. J. Sobie, R. J. Barlow, P. Scharff-Hansen, E. Torrence, A. Gupta, Dave Charlton, P. F. Åkesson, Giovanni Abbiendi, D. Axen, Oana Elena Vickey Boeriu, P. Amaral, Gideon Alexander, K. J. Anderson, F. Spano, R. G. Kellogg, Joost Vossebeld, Sachio Komamiya, Graham Wilson, Matthias Schröder, Klaus Desch, P. J. Bell, Peter Sherwood, Csaba Hajdu, L. Zivkovic, D. J. Miller, Stefano Marcellini, J. Ludwig, P. Mättig, Shoji Asai, Satoshi Mihara, Shlomo Dado, Ehud Duchovni, A. M. Smith, J. R. Carter, Katja Klein, K. Runge, P. Bock, Achim Stahl, James Letts, W. Menges, Otmar Biebel, D. Waller, K. Kruger, T. Saeki, R. D. Heuer, A. Michelini, Andris Skuja, T. Schörner-Sadenius, J. von Krogh, H. Landsman, Guenter Duckeck, Kiyotomo Kawagoe, P. S. Wells, Frank Fiedler, D. Toya, T. Kobayashi, Tetsuro Mashimo, M. F. Turner-Watson, A. Ludwig, Claudia Ciocca, K. Sachs, H. Nanjo, Terry Richard Wyatt, A. T. Watson, S. Campana, Giora Mikenberg, Philip Bechtle, M. Kupper, E. L. Barberio, R. J. Hawkings, Norbert Wermes, T. Kawamoto, D. Wetterling, S. Orito, J. Dubbert, R. K. Carnegie, J. A. Wilson, H. Voss, G. Giacomelli, A. De Roeck, M. Kobel, Frans Meijers, Alain Bellerive, G. Anagnostou, Pamela Ferrari, J. G. Layter, and R. Vértesi

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Branching fraction, High Energy Physics::Phenomenology, Hadron, Scalar boson, 01 natural sciences, Standard Model, Nuclear physics, Pair production, 0103 physical sciences, Higgs boson, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Boson, Event generator
Abstract

A search for the Higgsstrahlung process e + e − → hZ is described, where the neutral Higgs boson h is assumed to decay into hadronic final states. In order to be sensitive to a broad range of models, the search is performed independent of the flavour content of the Higgs boson decay. The analysis is based on e + e − collision data collected by the OPAL detector at energies between 192 and 209 GeV. The search does not reveal any significant excess over the Standard Model background prediction. Results are combined with previous searches at energies around 91 and at 189 GeV. A limit is set on the product of the cross-section and the hadronic branching ratio of the Higgs boson, as a function of the Higgs boson mass. Assuming the hZ coupling predicted by the Standard Model, and a Higgs boson decaying only into hadronic final states, a lower bound of 104 GeV / c 2 is set on the mass at the 95% confidence level.

Published
2004
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3. Search for the single production of doubly-charged Higgs bosons and constraints on their couplings from Bhabha scattering

Author

C. F. Vollmer, Jochen Schieck, R. J. Barlow, Alexander Oh, I. Nakamura, D. Lanske, Graham Wilson, Gunter Wolf, K. Stephens, N. Kanaya, Tara Shears, Shlomo Dado, D. Karlen, H. Mes, I. P. Duerdoth, S. Braibant, K. Hoffman, A. Leins, P. Gagnon, S. Yamashita, P. Igo-Kemenes, K. Ishii, H. Jeremie, Richard Teuscher, D. Toya, Giora Mikenberg, Arnulf Quadt, O. Schaile, H. Landsman, P. M. Watkins, J. Grunhaus, P. J. Bell, L. Brigliadori, T. Kuhl, R. J. Batley, M. J. Oreglia, A. D. Schaile, Gabriella Pasztor, P. Vannerem, D. R. Ward, Yoram Rozen, Zoltan Laszlo Trocsanyi, Dong Hee Kim, G. Gaycken, L. L. Kormos, G. Anagnostou, Richard J. K. Taylor, Gideon Bella, James Pinfold, R. Seuster, L. Zivkovic, E. L. Barberio, P. Renkel, M. Schumacher, A. J. Martin, H. J. Burckhart, M. Groll, Silvia Arcelli, D. E. Plane, S. W. O'Neale, C. P. Ward, Satoshi Mihara, P. O. Günther, Erez Etzion, J. R. Carter, G. N. Patrick, Katja Klein, Junichi Kanzaki, J. Polok, Stefan Kluth, Shlomit Tarem, W. Menges, Otmar Biebel, S. Söldner-Rembold, Sachio Komamiya, K. Buesser, E. A. De Wolf, Pamela Ferrari, J. G. Layter, M. Giunta, Georges Azuelos, K. J. Anderson, Daniel Lellouch, P. Amaral, J. A. McKenna, W. Mader, E. Tsur, C. M. Hawkes, J. Goldberg, Frank Fiedler, H. Nanjo, D. Waller, Takehiko Mori, A. Okpara, D. Axen, Oana Elena Vickey Boeriu, K. Kruger, T. Saeki, Gianni Masetti, C. Y. Chang, P. Tran, Matthias Schröder, Norbert Wermes, T. Kawamoto, C. Pahl, D. J. Miller, F. Spano, Peter Sherwood, Isabel Marian Trigger, K. W. Bell, G. D. Lafferty, S. Orito, H. Voss, T. J. McMahon, J. C. Hill, J. Ludwig, Christoph Rembser, P. Scharff-Hansen, K. Runge, S. Moed, P. Bock, Tobias Kramer, W. J. McDonald, B. C. Shen, P. F. Åkesson, Klaus Rabbertz, R. J. Hemingway, M. Donkers, Siegfried Bethke, M. A. Thomson, Stephen Lloyd, J. Dubbert, Robert Vertesi, R. K. Carnegie, T. Schörner-Sadenius, J. Lillich, G. Giacomelli, W. G. Scott, Dave Charlton, M. Gruwé, Raimund Ströhmer, A. M. Smith, A. Mutter, C. Hensel, A. De Roeck, M. Kobel, P. Jovanovic, E. K. U. Gross, Peter Krieger, J. W. Gary, Ehud Duchovni, Andris Skuja, T. Behnke, Frans Meijers, Guenter Duckeck, K. Harder, Richard Nisius, Tetsuro Mashimo, M. F. Turner-Watson, A. Macpherson, A. Michelini, Shoji Asai, Marek Tasevsky, Paolo Giacomelli, Dezso Horvath, R. D. Heuer, J. A. Wilson, Marco Cuffiani, M. Kupper, Beatrix Dienes, T. Kobayashi, S. Campana, J. M. Roney, R. M. Brown, Lorne Levinson, M. Harin-Dirac, Koichi Nagai, B. W. Kennedy, I. R. Bailey, W. Mohr, G. Karapetian, Gideon Alexander, Achim Stahl, E. Torrence, A. Gupta, A. Csilling, S. Rosati, A. Harel, Ikuo Ueda, D. M. Strom, J. Lu, M. Hamann, Richard Keeler, R. J. Sobie, Joost Vossebeld, Klaus Desch, T. R. Junk, P. S. Wells, Robert McPherson, J. von Krogh, Terry Richard Wyatt, A. T. Watson, Fabrizio Fabbri, A. Frey, R. J. Hawkings, D. Wetterling, M. Przybycień, A. A. Carter, M. Verzocchi, Giovanni Abbiendi, Christoph Geich-Gimbel, A. Fürtjes, Lutz Feld, M. Boutemeur, F. S. Merritt, Kiyotomo Kawagoe, G. P. Siroli, Christoph Schwick, Thorsten Wengler, B. Caron, Gabriele Benelli, M. Hauschild, Gregor Herten, J. E. Pilcher, N. K. Watson, C. Ainsley, P. Mättig, Alain Bellerive, B. Poli, K. Sachs, Philip Bechtle, Oliver Pooth, John Allison, R. G. Kellogg, Csaba Hajdu, Stefano Marcellini, James Letts, D. Zer-Zion, F. K. Loebinger, Ivor Fleck, Joleen Pater, Edward K. G. Sarkisyan, A. Klier, Balazs Ujvari, H. A. Neal, Gordon H. Hanson, and M. Ford

Subjects
Physics, Particle physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Electron–positron annihilation, High Energy Physics::Phenomenology, Yukawa potential, FOS: Physical sciences, 01 natural sciences, Lepton number, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), 0103 physical sciences, Higgs boson, High Energy Physics::Experiment, 010306 general physics, Particle Physics - Experiment, Lepton, Event generator, Bhabha scattering, Boson
Abstract

A search for single production of doubly-charged Higgs bosons has been performed using 600.7 pb^-1 of e+e- collision data with sqrt(s)=189--209GeV collected by the OPAL detector at LEP. No evidence for the existence of H++/-- is observed. Upper limits on the Yukawa coupling of the H++/-- to like-signed electron pairs are derived. Additionally, indirect constraints on the Yukawa coupling from Bhabha scattering, where the H++/-- would contribute via t-channel exchange, are derived for M(H++/--) < 2TeV. These are the first results for both a single production search and constraints from Bhabha scattering reported from LEP., 20 pages, 9 figures, Submitted to Phys. Lett. B

Published
2003
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4. Search for stable and long-lived massive charged particles in e+e− collisions at =130209 GeV

Author

D. Axen, Oana Elena Vickey Boeriu, James Pinfold, W. J. McDonald, R. Seuster, C. F. Vollmer, F. Spano, Gideon Bella, H. J. Burckhart, Peter Sherwood, B. C. Shen, Jochen Schieck, P. Mättig, Shoji Asai, R. J. Barlow, J. Ludwig, K. Runge, P. Bock, A. D. Schaile, Gabriella Pasztor, G. P. Siroli, Daniel Lellouch, Christoph Schwick, M. Donkers, Takehiko Mori, A. Okpara, Siegfried Bethke, P. Vannerem, P. F. Åkesson, W. G. Scott, D. E. Plane, C. P. Ward, P. Tran, C. Hensel, S. Söldner-Rembold, J. W. Gary, H. Mes, Alexander Oh, Kiyotomo Kawagoe, J. Goldberg, L. L. Kormos, T. Behnke, Oliver Pooth, K. Hoffman, John Allison, I. Nakamura, H. Landsman, S. Yamashita, P. Igo-Kemenes, Ehud Duchovni, A. Leins, D. Lanske, I. P. Duerdoth, S. Braibant, Dave Charlton, A. J. Martin, W. Menges, Otmar Biebel, P. Gagnon, L. Brigliadori, R. K. Keeler, Guenter Duckeck, K. Ishii, H. Jeremie, Marek Tasevsky, Dezso Horvath, E. Torrence, A. Gupta, A. Csilling, Graham Wilson, M. Gruwé, N. K. Watson, Zoltan Laszlo Trocsanyi, Dong Hee Kim, Yoram Rozen, Shlomo Dado, Arnulf Quadt, W. Mader, P. M. Watkins, R. D. Heuer, Richard Nisius, D. Toya, A. Michelini, Tara Shears, R. G. Kellogg, E. L. Barberio, K. Harder, O. Schaile, T. Kuhl, T. Kobayashi, Christoph Rembser, Richard J. K. Taylor, Erez Etzion, Giora Mikenberg, R. J. Batley, Csaba Hajdu, Marco Cuffiani, Junichi Kanzaki, J. Polok, Stefano Marcellini, S. Campana, P. Renkel, R. M. Brown, Stefan Kluth, K. Buesser, G. Gaycken, C. Ainsley, Lorne Levinson, Silvia Arcelli, Shlomit Tarem, James Letts, P. J. Bell, M. A. Thomson, S. W. O'Neale, R. J. Hemingway, I. R. Bailey, Georges Azuelos, M. Schumacher, E. Tsur, E. K. U. Gross, J. Lillich, C. M. Hawkes, P. O. Günther, B. W. Kennedy, E. A. De Wolf, M. Giunta, P. Jovanovic, Isabel Marian Trigger, K. W. Bell, Norbert Wermes, Peter Krieger, T. Kawamoto, Gideon Alexander, Gordon H. Hanson, Gunter Wolf, H. Nanjo, P. Amaral, J. C. Hill, Tobias Kramer, Richard Teuscher, M. Ford, J. M. Roney, K. J. Anderson, C. Pahl, D. Karlen, Koichi Nagai, S. Orito, W. Mohr, Raimund Ströhmer, Klaus Rabbertz, B. Poli, Stephen Lloyd, T. R. Wyatt, George Lafferty, Satoshi Mihara, M. J. Oreglia, Katja Klein, K. Sachs, Philip Bechtle, L. Zivkovic, D. Zer-Zion, J. R. Carter, G. N. Patrick, F. K. Loebinger, Ivor Fleck, Frank Fiedler, K. Stephens, N. Kanaya, Joleen Pater, Edward K. G. Sarkisyan, A. Klier, Beatrix Dienes, Balazs Ujvari, H. A. Neal, M. Boutemeur, F. S. Merritt, Gianni Masetti, C. Y. Chang, D. R. Ward, J. A. McKenna, S. Moed, Christoph Geich-Gimbel, J. Grunhaus, A. Fürtjes, Lutz Feld, M. Hamann, Sachio Komamiya, R. J. Sobie, Thorsten Wengler, Joost Vossebeld, B. Caron, D. Waller, K. Kruger, T. Saeki, Klaus Desch, Gabriele Benelli, P. Scharff-Hansen, A. M. Smith, Andris Skuja, Tetsuro Mashimo, M. F. Turner-Watson, A. Macpherson, T. R. Junk, A. Mutter, M. Kupper, P. S. Wells, M. Hauschild, A. T. Watson, Matthias Schröder, T. J. McMahon, Achim Stahl, D. J. Miller, J. Dubbert, Robert Vertesi, R. K. Carnegie, S. Rosati, J. A. Wilson, Gregor Herten, Robert McPherson, G. Karapetian, A. Harel, T. Schörner-Sadenius, Alain Bellerive, Ikuo Ueda, D. M. Strom, J. Lu, Fabrizio Fabbri, A. Frey, J. E. Pilcher, M. Przybycień, A. A. Carter, M. Verzocchi, G. Anagnostou, Paolo Giacomelli, Giovanni Abbiendi, J. von Krogh, M. Harin-Dirac, R. J. Hawkings, D. Wetterling, Pamela Ferrari, J. G. Layter, H. Voss, G. Giacomelli, A. De Roeck, M. Kobel, and Frans Meijers

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Particle physics, Muon, 010308 nuclear & particles physics, Scalar (mathematics), Supersymmetry, 01 natural sciences, Electric charge, Charged particle, Nuclear physics, Chargino, 0103 physical sciences, High Energy Physics::Experiment, 010306 general physics, Particle Physics - Experiment, Lepton
Abstract

A search for stable and long-lived massive particles of electric charge |Q/e|=1 or fractional charges of 2/3, 4/3, and 5/3 is reported using data collected by the OPAL detector at LEP, at centre-of-mass energies from 130 to 209 GeV. These particles are assumed to be pair-produced in e+e- collisions and not to interact strongly. No evidence for the production of these particles was observed. Model-independent upper limits on the production cross-section between 0.005 and 0.028 pb have been derived for scalar and spin-1/2 particles with charge +-1. Within the framework of the Constrained Minimal Supersymmetric Standard Model (CMSSM), this implies a lower limit of 98.0 (98.5) GeV on the mass of long-lived right (left)- handed scalar muons and scalar taus. Long-lived charged heavy leptons and charginos are excluded for masses below 102.0 GeV. For particles with fractional charge +-2/3, +-4/3, and +-5/3, the upper limit on the production cross-section varies between 0.005 and 0.020 pb. All mass and cross-section limits are derived at the 95% confidence level and are valid for particles with lifetimes longer than 10-6s. A search for stable and long-lived massive particles of electric charge | Q / e |=1 or fractional charges of 2/3, 4/3, and 5/3 is reported using data collected by the OPAL detector at LEP, at centre-of-mass energies from 130 to 209 GeV. These particles are assumed to be pair-produced in e + e − collisions and not to interact strongly. No evidence for the production of these particles was observed. Model-independent upper limits on the production cross-section between 0.005 and 0.028 pb have been derived for scalar and spin-1/2 particles with charge ±1. Within the framework of the Constrained Minimal Supersymmetric Standard Model (CMSSM), this implies a lower limit of 98.0 (98.5) GeV on the mass of long-lived right- (left-)handed scalar muons and scalar taus. Long-lived charged heavy leptons and charginos are excluded for masses below 102.0 GeV. For particles with fractional charge ±2/3, ±4/3 and ±5/3, the upper limit on the production cross-section varies between 0.005 and 0.020 pb. All mass and cross-section limits are derived at the 95% confidence level and are valid for particles with lifetimes longer than 10 −6 s. A search for stable and long-lived massive particles of electric charge |Q/e|=1 or fractional charges of 2/3, 4/3, and 5/3 is reported using data collected by the OPAL detector at LEP, at centre-of-mass energies from 130 to 209 GeV. These particles are assumed to be pair-produced in e+e- collisions and not to interact strongly. No evidence for the production of these particles was observed. Model-independent upper limits on the production cross-section between 0.005 and 0.028 pb have been derived for scalar and spin-1/2 particles with charge +-1. Within the framework of the Constrained Minimal Supersymmetric Standard Model (CMSSM), this implies a lower limit of 98.0 (98.5) GeV on the mass of long-lived right (left)- handed scalar muons and scalar taus. Long-lived charged heavy leptons and charginos are excluded for masses below 102.0 GeV. For particles with fractional charge +-2/3, +-4/3, and +-5/3, the upper limit on the production cross-section varies between 0.005 and 0.020 pb. All mass and cross-section limits are derived at the 95% confidence level and are valid for particles with lifetimes longer than 10-6s.

Published
2003
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5. A measurement of the τ−→μ−ν̄μντ branching ratio

Author

G Abbiendi, C Ainsley, P.F Åkesson, G Alexander, J Allison, P Amaral, G Anagnostou, K.J Anderson, S Arcelli, S Asai, D Axen, G Azuelos, I Bailey, E Barberio, R.J Barlow, R.J Batley, P Bechtle, T Behnke, K.W Bell, P.J Bell, G Bella, A Bellerive, G Benelli, S Bethke, O Biebel, I.J Bloodworth, O Boeriu, P Bock, D Bonacorsi, M Boutemeur, S Braibant, L Brigliadori, R.M Brown, K Buesser, H.J Burckhart, S Campana, R.K Carnegie, B Caron, A.A Carter, J.R Carter, C.Y Chang, D.G Charlton, A Csilling, M Cuffiani, S Dado, S Dallison, A De Roeck, E.A De Wolf, K Desch, B Dienes, M Donkers, J Dubbert, E Duchovni, G Duckeck, I.P Duerdoth, E Elfgren, E Etzion, F Fabbri, L Feld, P Ferrari, F Fiedler, I Fleck, M Ford, A Frey, A Fürtjes, P Gagnon, J.W Gary, G Gaycken, C Geich-Gimbel, G Giacomelli, P Giacomelli, M Giunta, J Goldberg, E Gross, J Grunhaus, M Gruwé, P.O Günther, A Gupta, C Hajdu, M Hamann, G.G Hanson, K Harder, A Harel, M Harin-Dirac, M Hauschild, J Hauschildt, C.M Hawkes, R Hawkings, R.J Hemingway, C Hensel, G Herten, R.D Heuer, J.C Hill, K Hoffman, R.J Homer, D Horváth, R Howard, P Igo-Kemenes, K Ishii, H Jeremie, P Jovanovic, T.R Junk, N Kanaya, J Kanzaki, G Karapetian, D Karlen, V Kartvelishvili, K Kawagoe, T Kawamoto, R.K Keeler, R.G Kellogg, B.W Kennedy, D.H Kim, K Klein, A Klier, S Kluth, T Kobayashi, M Kobel, S Komamiya, L Kormos, T Krämer, T Kress, P Krieger, J von Krogh, D Krop, K Kruger, T Kuhl, M Kupper, G.D Lafferty, H Landsman, D Lanske, J.G Layter, A Leins, D Lellouch, L Levinson, J Lillich, S.L Lloyd, F.K Loebinger, J Lu, J Ludwig, A Macpherson, W Mader, S Marcellini, T.E Marchant, A.J Martin, J.P Martin, G Masetti, T Mashimo, W.J McDonald, J McKenna, T.J McMahon, R.A McPherson, F Meijers, P Mendez-Lorenzo, W Menges, F.S Merritt, H Mes, A Michelini, S Mihara, G Mikenberg, D.J Miller, S Moed, W Mohr, T Mori, A Mutter, K Nagai, I Nakamura, H.A Neal, R Nisius, S.W O'Neale, A Oh, A Okpara, M.J Oreglia, S Orito, C Pahl, G Pásztor, J.R Pater, G.N Patrick, J.E Pilcher, J Pinfold, D.E Plane, B Poli, J Polok, O Pooth, M Przybycień, A Quadt, K Rabbertz, C Rembser, P Renkel, H Rick, J.M Roney, S Rosati, Y Rozen, K Runge, K Sachs, T Saeki, O Sahr, E.K.G Sarkisyan, A.D Schaile, O Schaile, P Scharff-Hansen, J Schieck, T Schörner-Sadenius, M Schröder, M Schumacher, C Schwick, W.G Scott, R Seuster, T.G Shears, B.C Shen, P Sherwood, G Siroli, A Skuja, A.M Smith, R Sobie, S Söldner-Rembold, F Spano, A Stahl, K Stephens, D Strom, R Ströhmer, S Tarem, M Tasevsky, R.J Taylor, R Teuscher, M.A Thomson, E Torrence, D Toya, P Tran, T Trefzger, A Tricoli, I Trigger, Z Trócsányi, E Tsur, M.F Turner-Watson, I Ueda, B Ujvári, B Vachon, C.F Vollmer, P Vannerem, M Verzocchi, H Voss, J Vossebeld, D Waller, C.P Ward, D.R Ward, P.M Watkins, A.T Watson, N.K Watson, P.S Wells, T Wengler, N Wermes, D Wetterling, G.W Wilson, J.A Wilson, G Wolf, T.R Wyatt, S Yamashita, D Zer-Zion, L Zivkovic, J Letts, P Mättig, and OPAL Collaboration

Subjects
Physics, Coupling constant, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Branching fraction, High Energy Physics::Phenomenology, 01 natural sciences, Nuclear physics, 0103 physical sciences, Higgs boson, High Energy Physics::Experiment, 010306 general physics, Lepton, Minimal Supersymmetric Standard Model
Abstract

The tau -> mu nu nu branching ratio has been measured using data collected from 1990 to 1995 by the OPAL detector at the LEP collider. The resulting value of B(tau -> mu nu nu) = 0.1734 +- 0.0009(stat) +- 0.0006(syst) has been used in conjunction with other OPAL measurements to test lepton universality, yielding the coupling constant ratios gmu/ge=1.0005+-0.0044 and gt/ge=1.0031+-0.0048, in good agreement with the Standard Model prediction of unity. A value for the Michel parameter eta = 0.004 +- 0.037 has also been determined and used to find a limit for the mass of the charged Higgs boson mH+- > 1.25 tan beta, in the Minimal Supersymmetric Standard Model.

Published
2003
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6. Test of non-commutative QED in the process e+e−→γγ at LEP

Author

E. Torrence, A. Gupta, D. E. Plane, P. Tran, James Pinfold, R. Seuster, Thorsten Wengler, K. Harder, Achim Stahl, W. J. McDonald, B. C. Shen, R. M. Brown, Lorne Levinson, Graham Wilson, I. R. Bailey, B. Caron, Matthias Schröder, J. M. Roney, S. Yamashita, Shlomo Dado, M. Donkers, Siegfried Bethke, G. P. Siroli, W. G. Scott, I. Nakamura, H. Mes, D. Axen, Christoph Schwick, D. Toya, Ehud Duchovni, Gabriele Benelli, Gunter Wolf, K. Sachs, Oliver Pooth, John Allison, P. Igo-Kemenes, Philip Bechtle, R. K. Keeler, A. Tricoli, I. P. Duerdoth, J. W. Gary, I. J. Bloodworth, Koichi Nagai, M. J. Oreglia, Giora Mikenberg, Oana Elena Vickey Boeriu, Kiyotomo Kawagoe, Arnulf Quadt, K. Ishii, P. M. Watkins, H. Jeremie, L. Zivkovic, Richard Teuscher, P. Scharff-Hansen, S. Braibant, J. R. Carter, Dave Charlton, T. Schörner-Sadenius, G. N. Patrick, A. D. Schaile, Gabriella Pasztor, S. Rosati, Marek Tasevsky, M. Boutemeur, F. S. Merritt, A. Michelini, D. J. Miller, P. Renkel, E. Elfgren, A. Harel, L. L. Kormos, M. Gruwé, R. G. Kellogg, W. Menges, Otmar Biebel, F. Spano, Peter Sherwood, J. Ludwig, K. Runge, P. Bock, W. Mohr, A. M. Smith, M. Hauschild, Silvia Arcelli, P. Vannerem, C. P. Ward, S. Söldner-Rembold, N. K. Watson, Yoram Rozen, J. Grunhaus, A. J. Martin, K. Hoffman, A. Leins, Csaba Hajdu, Norbert Wermes, Richard Nisius, R. J. Batley, T. Kawamoto, T. Kobayashi, C. Ainsley, Ikuo Ueda, D. M. Strom, S. Orito, Andris Skuja, P. Gagnon, Stefano Marcellini, G. Gaycken, R. J. Hemingway, W. Mader, R. D. Heuer, M. Schumacher, J. Lu, Richard J. K. Taylor, Georges Azuelos, A. Csilling, E. Tsur, E. A. De Wolf, J. Lillich, Tara Shears, Junichi Kanzaki, C. Pahl, Tetsuro Mashimo, James Letts, G. D. Lafferty, M. F. Turner-Watson, J. Polok, D. Karlen, Erez Etzion, C. M. Hawkes, Zoltan Laszlo Trocsanyi, Dong Hee Kim, H. Rick, P. Amaral, Gideon Bella, A. Macpherson, Isabel Marian Trigger, K. W. Bell, O. Schaile, K. Buesser, P. Jovanovic, H. J. Burckhart, Marco Cuffiani, Stefan Kluth, J. C. Hill, T. Kuhl, D. Zer-Zion, M. Kupper, Shlomit Tarem, Peter Krieger, B. Poli, Tobias Kramer, P. F. Åkesson, F. K. Loebinger, D. Horváth, B. W. Kennedy, M. Hamann, J. A. McKenna, Gregor Herten, Ivor Fleck, C. Hensel, Sachio Komamiya, M. Giunta, Joleen Pater, P. J. Bell, E. K. U. Gross, Edward K. G. Sarkisyan, H. Landsman, J. Goldberg, P. Mättig, A. Klier, Shoji Asai, R. J. Sobie, Gideon Alexander, T. Behnke, Joost Vossebeld, Alexander Oh, J. E. Pilcher, Klaus Desch, Balazs Ujvari, H. A. Neal, Daniel Lellouch, S. Campana, E. L. Barberio, Robert McPherson, Takehiko Mori, A. Okpara, M. A. Thomson, D. Lanske, D. Waller, Fabrizio Fabbri, A. Frey, Christoph Geich-Gimbel, K. Kruger, T. Saeki, Klaus Rabbertz, T. R. Junk, Stephen Lloyd, Christoph Rembser, Gordon H. Hanson, M. Ford, P. S. Wells, C. F. Vollmer, Terry Richard Wyatt, A. T. Watson, Jochen Schieck, R. J. Barlow, A. Fürtjes, Guenter Duckeck, Lutz Feld, A. Mutter, Gianni Masetti, C. Y. Chang, S. Moed, L. Brigliadori, S. W. O'Neale, P. O. Günther, Daniele Bonacorsi, K. J. Anderson, Raimund Ströhmer, J. von Krogh, Satoshi Mihara, Beatrix Dienes, Katja Klein, R. J. Hawkings, D. Wetterling, Frank Fiedler, H. Voss, T. Kress, A. A. Carter, G. Giacomelli, A. De Roeck, M. Kobel, Paolo Giacomelli, M. Verzocchi, Giovanni Abbiendi, M. Przybycien, M. Harin-Dirac, R. J. Homer, Frans Meijers, T. J. McMahon, J. Dubbert, Robert Vertesi, R. K. Carnegie, Pamela Ferrari, J. G. Layter, J. A. Wilson, G. Karapetian, K. Stephens, N. Kanaya, Alain Bellerive, D. R. Ward, and G. Anagnostou

Subjects
Physics, Particle physics, Nuclear and High Energy Physics, Photon, Scale (ratio), 010308 nuclear & particles physics, Space (mathematics), Rotation, 01 natural sciences, law.invention, law, Orientation (geometry), 0103 physical sciences, Annihilation radiation, 010306 general physics, Collider, Energy (signal processing)
Abstract

Non-commutative QED would lead to deviations from the Standard Model depending on a new energy scale ΛNC and a unique direction in space defined by two angles η and ξ. In this analysis, η is defined as the angle between the unique direction and the rotation axis of the earth. The predictions of a tree level calculation for the process e+e−→γγ are evaluated for the specific orientation of the OPAL detector and compared to the measurements. Distributions of the polar and azimuthal photon angles are used to extract limits on the energy scale ΛNC depending on the model parameter η. It is shown that the time dependence of the total cross-section could be used to determine the model parameter ξ if there were a detectable signal. This is the first experimental study of non-commutative QED at an e+e− collider.

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