Photonic events with missing energy in e+e- collisions at √s = 189 GeV

G. Abbiendi, K. Ackerstaff, C. Ainsley, P. F. Akesson, G. Alexander, J. Allison, K. J. Anderson, S. Arcelli, S. Asai, S. F. Ashby, D. Axen, G. Azuelos, I. Bailey, A. H. Ball, E. Barberio, R. J. Barlow, J. R. Batley, S. Baumann, T. Behnke, K. W. BellG. Bella, A. Bellerive, S. Bentvelsen, S. Bethke, O. Biebel, I. J. Bloodworth, P. Bock, J. Böhme, O. Boeriu, D. Bonacorsi, M. Boutemeur, S. Braibant, P. Bright-Thomas, L. Brigliadori, R. M. Brown, H. J. Burckhart, J. Cammin, P. Capiluppi, R. K. Carnegie, A. A. Carter, J. R. Carter, C. Y. Chang, D. G. Charlton, C. Ciocca, P. E.L. Clarke, E. Clay, I. Cohen, O. C. Cooke, J. Couchman, C. Couyoumtzelis, R. L. Coxe, M. Cuffiani, S. Dado, G. M. Dallavalle, S. Dallison, R. Davis, A. de Roeck, P. Dervan, K. Desch, B. Dienes, M. S. Dixit, M. Donkers, J. Dubbert, E. Duchovni, G. Duckeck, I. P. Duerdoth, P. G. Estabrooks, E. Etzion, F. Fabbri, M. Fanti, A. A. Faust, L. Feld, P. Ferrari, F. Fiedler, I. Fleck, M. Ford, A. Frey, A. Fürtjes, D. I. Futyan, P. Gagnon, J. W. Gary, G. Gaycken, C. Geich-Gimbel, G. Giacomelli, P. Giacomelli, D. M. Gingrich, D. Glenzinski, J. Goldberg, C. Grandi, K. Graham, E. Gross, J. Grunhaus, M. Gruwé, P. O. Günther, M. Hansroul, M. Hapke, K. Harder, A. Harel, C. K. Hargrove, M. Harin-Dirac, A. Hauke, M. Hauschild, C. M. Hawkes, R. Hawkings, R. J. Hemingway, C. Hensel, G. Herten, R. D. Heuer, M. D. Hildreth, J. C. Hill, P. R. Hobson, A. Hocker, K. Hoffman, R. J. Homer, A. K. Honma, D. Horváth, K. R. Hossain, R. Howard, P. Huntemeyer, P. Igo-Kemenes, D. C. Imrie, K. Ishii, F. R. Jacob, A. Jawahery, H. Jeremie, C. R. Jones, P. Jovanovic, T. R. Junk, N. Kanaya, J. Kanzaki, G. Karapetian, D. Karlen, V. Kartvelishvili, K. Kawagoe, T. Kawamoto, P. I. Kayal, R. K. Keeler, R. G. Kellogg, B. W. Kennedy, D. H. Kim, K. Klein, A. Klier, T. Kobayashi, M. Kobel, T. P. Kokott, Sachio Komamiya, R. V. Kowalewski, T. Kress, P. Krieger, J. von Krogh, M. Kupper, P. Kyberd, G. D. Lafferty, H. Landsman, D. Lanske, I. Lawson, J. G. Layter, A. Leins, D. Lellouch, J. Letts, L. Levinson, R. Liebisch, J. Lillich, B. List, C. Littlewood, A. W. Lloyd, S. L. Lloyd, F. K. Loebinger, G. D. Long, M. J. Losty, J. Lu, J. Ludwig, A. Macchiolo, A. Macpherson, W. Mader, M. Mannelli, S. Marcellini, T. E. Marchant, A. J. Martin, J. P. Martin, G. Martinez, T. Mashimo, P. Mättig, W. J. McDonald, J. McKenna, T. J. McMahon, R. A. McPherson, F. Meijers, P. Mendez-Lorenzo, F. S. Merritt, H. Mes, A. Michelini, S. Mihara, G. Mikenberg, D. J. Miller, W. Mohr, A. Montanari, T. Mori, K. Nagai, I. Nakamura, H. A. Neal, R. Nisius, S. W. O'Neale, F. G. Oakham, F. Odorici, H. O. Ogren, A. Oh, A. Okpara, M. J. Oreglia, S. Orito, G. Pásztor, J. R. Pater, G. N. Patrick, J. Patt, P. Pfeifenschneider, J. E. Pilcher, J. Pinfold, D. E. Plane, B. Poli, J. Polok, O. Pooth, M. Przybycień, A. Quadt, C. Rembser, H. Rick, S. A. Robins, N. Rodning, J. M. Roney, S. Rosati, K. Roscoe, A. M. Rossi, Y. Rozen, K. Runge, O. Runolfsson, D. R. Rust, K. Sachs, T. Saeki, O. Sahr, W. M. Sang, E. K.G. Sarkisyan, C. Sbarra, A. D. Schaile, O. Schaile, P. Scharff-Hansen, S. Schmitt, M. Schröder, M. Schumacher, C. Schwick, W. G. Scott, R. Seuster, T. G. Shears, B. C. Shen, C. H. Shepherd-Themistocleous, P. Sherwood, G. P. Siroli, A. Skuja, A. M. Smith, G. A. Snow, R. Sobie, S. Söldner-Rembold, S. Spagnolo, M. Sproston, A. Stahl, K. Stephens, K. Stoll, D. Strom, R. Ströhmer, B. Surrow, S. D. Talbot, S. Tarem, R. J. Taylor, R. Teuscher, M. Thiergen, J. Thomas, M. A. Thomson, E. Torrence, S. Towers, T. Trefzger, I. Trigger, Z. Trócsányi, E. Tsur, M. F. Turner-Watson, I. Ueda, 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, G. W. Wilson, J. A. Wilson, T. R. Wyatt, S. Yamashita, V. Zacek, D. Zer-Zion

Research output: Contribution to journalArticle

81 Citations (Scopus)

Abstract

Photonic events with large missing energy have been observed in e+e- collisions at a centre-of-mass energy of 189 GeV using the OPAL detector at LEP. Results are presented for event topologies consistent with a single photon or with an acoplanar photon pair. Cross-section measurements are performed within the kinematic acceptance of each selection, and the number of light neutrino species is measured. Cross-section results are compared with the expectations from the Standard Model process e+e- → vv̄ + photon(s). No evidence is observed for new physics contributions to these final states. Upper limits on σ(e+e- → XY) · BR(X → Yγ) and σ(e+e- → XX) · BR2(X → Yγ) are derived for the case of stable and invisible Y. These limits apply to single and pair production of excited neutrinos (X = v*, Y = v), to neutralino production (X = χ̃02, Y = χ̃01) and to supersymmetric models in which X = χ̃01 and Y = G̃ is a light gravitino. The case of macroscopic decay lengths of particle X is considered for e+e- → XX, X → Yγ, when MY ≈ 0. The single-photon results are also used to place upper limits on superlight gravitino pair production as well as graviton-photon production in the context of theories with additional space dimensions.

Original languageEnglish
Pages (from-to)253-272
Number of pages20
JournalEuropean Physical Journal C
Volume18
Issue number2
DOIs
Publication statusPublished - 2000 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Engineering (miscellaneous)
  • Physics and Astronomy (miscellaneous)

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    Abbiendi, G., Ackerstaff, K., Ainsley, C., Akesson, P. F., Alexander, G., Allison, J., Anderson, K. J., Arcelli, S., Asai, S., Ashby, S. F., Axen, D., Azuelos, G., Bailey, I., Ball, A. H., Barberio, E., Barlow, R. J., Batley, J. R., Baumann, S., Behnke, T., ... Zer-Zion, D. (2000). Photonic events with missing energy in e+e- collisions at √s = 189 GeV. European Physical Journal C, 18(2), 253-272. https://doi.org/10.1007/s100520000522