1. Search for anomalous production of acoplanar di-lepton events in ${\rm e^+e^-}$ collisions at $\sqrt{s} =$ 183 and 189 GeV
- Author
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P. Ferrari, Randall Sobie, H. Mes, Naoko Kanaya, R. J. Hemingway, G. D. Lafferty, I. P. Duerdoth, S. Braibant, J. Lillich, Christopher Hawkes, German Martinez, K. Stephens, H. O. Ogren, B. W. Kennedy, P. Jovanovic, C. Littlewood, Christoph Geich-Gimbel, Gideon Bella, K. Stoll, Andris Skuja, S. Petzold, Austin Ball, Guenter Duckeck, A. A. Faust, P. Hüntemeyer, Daniel Lellouch, L. Brigliadori, H. J. Burckhart, Jacqueline Batley, Peter R Hobson, D. Zer-Zion, Takehiko Mori, Peter Krieger, Vakhtang Kartvelishvili, Tetsuro Mashimo, S. W. O'Neale, M. F. Turner-Watson, K. J. Anderson, Sachio Komamiya, A. Okpara, P. Mättig, T. J. McMahon, Richard Teuscher, R. Kowalewski, Erez Etzion, M. A. Thomson, A. T. Watson, Matthias Schröder, D. E. Plane, F. Fiedler, M. Thiergen, J. E. Conboy, A. Fürtjes, S. Arcelli, Alessandro Montanari, I. Meyer, C. Couyoumtzelis, T. P. Kokott, J. Dubbert, D. Waller, E. K. U. Gross, M. Verzocchi, W. Gorn, R. K. Carnegie, Shlomit Tarem, Lutz Feld, R. Van Kooten, T. Saeki, G. M. Dallavalle, Alessandra Fanfani, R. Davis, G. Gaycken, P. G. Bright-Thomas, J. A. Wilson, M. Sproston, C. R. Jones, J. Böhme, B. Surrow, M. Schumacher, M. Boutemeur, F. S. Merritt, Gideon Alexander, Thomas E Marchant, Paolo Capiluppi, Michael Hildreth, Achim Stahl, I. Trigger, Stefan Schmitt, Alain Bellerive, M. Kolrep, N. L. Rodning, T. Kuhl, Paul Kyberd, F. K. Loebinger, P. Dervan, S. Yamashita, P. Scharff-Hansen, B. Poli, F. Odorici, K. Graham, F. Wäckerle, D. R. Ward, Tara Shears, H. Voss, R. J. Barlow, Georges Azuelos, Ivor Fleck, Richard Nisius, B. List, Ekg Sarkisyan, D. M. Gingrich, P. Igo-Kemenes, E. Tsur, Ehud Duchovni, D. Axen, A. Jawahery, Oana Elena Vickey Boeriu, J. Grunhaus, J. Bechtluft, J. A. McKenna, D. J. Miller, Joleen Pater, K. W. Bell, J. Goldberg, Dave Charlton, Marco Cuffiani, K. Ishii, H. Jeremie, S. B. Anderson, Shoji Asai, M. Jimack, A. M. Smith, K. Hoffman, A. Klier, A. Michelini, Juergen Thomas, M. Przybycień, H. A. Neal, M. Fanti, T. Kress, J. C. Hill, J. M. Roney, S. Spagnolo, A. M. Rossi, W. R. Gibson, W. J. McDonald, B. C. Shen, A. A. Carter, I. J. Bloodworth, M. Donkers, Kiyotomo Kawagoe, K. Harder, Siegfried Bethke, D. Liu, A. K. Honma, Robert McPherson, Paolo Giacomelli, T. Kobayashi, Stan Bentvelsen, O. Schaile, M. Hansroul, Koichi Nagai, John Allison, W. G. Scott, J. Schieck, R. Hawkings, I. Nakamura, H. Landsman, Peter Sherwood, I. Cohen, R. D. Heuer, Christoph Rembser, James Pinfold, S. Robertson, Yoram Rozen, W. Mohr, Fabrizio Fabbri, A. Frey, R. Perez-Ochoa, R. Seuster, Giovanni Abbiendi, A. J. Martin, Claudia Ciocca, M. Harin-Dirac, S. A. Robins, R. L. Coxe, T. Trefzger, R. J. Homer, R. G. Kellogg, Junichi Kanzaki, J. Polok, R. M. Brown, D. Karlen, D. R. Rust, P. Mendez-Lorenzo, F. G. Oakham, R. Liebisch, K. Ackerstaff, Alexander Wagner, A. Macchiolo, J. Ludwig, A. Hocker, Daniele Bonacorsi, K. Runge, P. Bock, Lorne Levinson, Csaba Hajdu, D. Glenzinski, Dezso Horvath, M. J. Losty, Stefano Marcellini, E. L. Barberio, D. Chrisman, G. D. Long, V. Zacek, K. R. Hossain, W. M. Sang, J. Couchman, W. Mader, O. C. Cooke, P. Pfeifenschneider, J. W. Gary, Marcello Mannelli, C. K. Hargrove, Stephen Lloyd, J. Patt, D. C. Imrie, André Schöning, C. H. Shepherd-Themistocleous, J. von Krogh, O. Sahr, C. Sbarra, F. R. Jacob, G. P. Siroli, M. Gruwé, D. Wetterling, Christoph Schwick, K. Roscoe, P. Gagnon, S. Baumann, E. Torrence, Zoltan Laszlo Trocsanyi, E. Clay, Dong Hee Kim, J. Lauber, E. A. Mckigney, S. D. Talbot, T. Behnke, Satoshi Mihara, T. R. Junk, D. Lanske, D. I. Futyan, P. S. Wells, Terry Richard Wyatt, O. Runolfsson, P. G. Estabrooks, R. K. Keeler, N. K. Watson, Arnulf Quadt, P. M. Watkins, Claudio Grandi, J. S. White, M. Fierro, S. Rosati, A. Harel, Ikuo Ueda, D. M. Strom, A. D. Schaile, Gabriella Pasztor, J. Lu, P. Vannerem, G. A. Snow, C. P. Ward, Raimund Ströhmer, S. Söldner-Rembold, P. Poffenberger, Beatrix Dienes, J. Letts, C. Y. Chang, P. Taras, A. Macpherson, K. Sachs, Shlomo Dado, Giora Mikenberg, Klaus Desch, S. F. Ashby, R. Howard, Otmar Biebel, P. I. Kayal, Norbert Wermes, Sherry Towers, T. Kawamoto, S. Orito, S. Betts, M. Hapke, M. J. Oreglia, Gregor Herten, J. E. Pilcher, A. W. Lloyd, G. W. Wilson, M. Hauschild, S.J. Dallison, J. R. Carter, G. N. Patrick, A. Biguzzi, J. G. Layter, P. E.L. Clarke, J. P. Martin, S. De Jong, H. Rick, G. G. Hanson, G. Giacomelli, I. Lawson, A. De Roeck, M. Kobel, M. S. Dixit, and Frans Meijers
- Subjects
Physics ,Particle physics ,Physics and Astronomy (miscellaneous) ,Branching fraction ,Electron–positron annihilation ,High Energy Physics::Phenomenology ,Standard Model ,Nuclear physics ,Chargino ,Neutralino ,Higgs boson ,High Energy Physics::Experiment ,Nuclear Experiment ,Engineering (miscellaneous) ,Minimal Supersymmetric Standard Model ,Lepton - Abstract
A selection of di-lepton events with significant missing transverse momentum has been performed using a total data sample of 237.4 pb-1 at e+e- centre-of-rnass energies of approximately 183 GeV and 189 GeV. The observed numbers of events - 78 at 183 GeV and 301 at 189 GeV - are consistent with the numbers expected from Standard Model processes, which arise predominantly from W+W- production with both W bosons decaying leptonically. This topology is also an experimental signature for the pair production of new particles that decay to a charged lepton accompanied by one or more invisible particles. Discrimination techniques are described that optimise the sensitivity to particular new physics channels. No evidence for new phenomena is apparent. Upper limits on the production cross-section times branching ratio squared for sleptons and for leptonically decaying charginos and charged Higgs are presented in a manner intended to minimise the number of model assumptions. Assuming a 100% branching ratio for the decay l±R → l±χ01, where χ01 is the lightest neutralino, we exclude at 95% CL: right-handed smuons with masses below 82.3 GeV for mμ- - mχ01 > 3 GeV and right-handed staus with masses below 81.0 GeV for mτ- -mχ01 > 8 GeV. Right-handed selectrons are excluded at 95% CL for masses below 87.1 GeV for mẽ - mχ01 > 5 GeV, within the framework of the Minimal Supersymmetric Standard Model assuming μ, < - 100 GeV and tan β= 1.5. Charged Higgs bosons, H±, are excluded at 95% CL for masses below 82.8 GeV, assuming a 100% branching ratio for the decay H± → τ ± vτ.
- Published
- 2000