Multi-photon events with large missing energy in e+e- collisions at √s = 192-209 GeV

G. Abbiendi, C. Ainsley, P. F. Akesson, G. Alexander, J. Allison, P. Amaral, G. Anagnostou, K. J. Anderson, S. Arcelli, S. Asai, D. Axen, G. Azuelos, I. Bailey, E. Barberio, T. Barillari, R. J. Barlow, R. J. Batley, P. Bechtle, T. Behnke, K. W. BellP. J. Bell, G. Bella, A. Bellerive, G. Benelli, S. Bethke, O. Biebel, O. Boeriu, P. Bock, M. Boutemeur, S. Braibant, L. Brigliadori, R. M. Brown, K. Buesser, H. J. Burckhart, S. Campana, R. K. Carnegie, A. A. Carter, J. R. Carter, C. Y. Chang, D. G. Charlton, C. Ciocca, A. Csilling, M. Cuffiani, S. Dado, A. de Roeck, E. A. de Wolf, K. Desch, B. Dienes, M. Donkers, J. Dubbert, E. Duchovni, G. Duckeck, I. P. Duerdoth, E. Etzion, F. Fabbri, L. Feld, P. Ferrari, F. Fiedler, I. Fleck, M. Ford, A. Frey, 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, A. Harel, M. Hauschild, C. M. Hawkes, R. Hawkings, R. J. Hemingway, G. Herten, R. D. Heuer, J. C. Hill, K. Hoffman, D. Horváth, P. Igo-Kemenes, K. Ishii, H. Jeremie, P. Jovanovic, T. R. Junk, N. Kanaya, J. Kanzaki, D. Karlen, K. Kawagoe, T. Kawamoto, R. K. Keeler, R. G. Kellogg, B. W. Kennedy, S. Kluth, T. Kobayashi, M. Kobel, S. Komamiya, T. Krämer, P. Krieger, J. von Krogh, K. Kruger, T. Kuhl, M. Kupper, G. D. Lafferty, H. Landsman, D. Lanske, J. G. Layter, D. Lellouch, J. Letts, L. Levinson, J. Lillich, S. L. Lloyd, F. K. Loebinger, J. Lu, A. Ludwig, J. Ludwig, W. Mader, S. Marcellini, A. J. Martin, G. Masetti, T. Mashimo, P. Mättig, J. McKenna, R. A. McPherson, F. Meijers, W. Menges, F. S. Merritt, H. Mes, N. Meyer, A. Michelini, S. Mihara, G. Mikenberg, D. J. Miller, S. Moed, W. Mohr, T. Mori, A. Mutter, K. Nagai, I. Nakamura, H. Nanjo, H. A. Neal, R. Nisius, S. W. O'Neale, A. Oh, M. J. Oreglia, S. Orito, C. Pahl, G. Pásztor, J. R. Pater, J. E. Pilcher, J. Pinfold, D. E. Plane, B. Poli, O. Pooth, M. Przybycień, A. Quadt, K. Rabbertz, C. Rembser, P. Renkel, J. M. Roney, Y. Rozen, K. Runge, K. Sachs, T. Saeki, E. K.G. Sarkisyan, A. D. Schaile, O. Schaile, P. Scharff-Hansen, J. Schieck, T. Schörner-Sadenius, M. Schröder, M. Schumacher, W. G. Scott, R. Seuster, T. G. Shears, B. C. Shen, P. Sherwood, A. Skuja, A. M. Smith, R. Sobie, S. Söldner-Rembold, F. Spano, A. Stahl, D. Strom, R. Ströhmer, S. Tarem, M. Tasevsky, R. Teuscher, M. A. Thomson, E. Torrence, D. Toya, P. Tran, I. Trigger, Z. Trócsányi, E. Tsur, M. F. Turner-Watson, I. Ueda, B. Ujvári, C. F. Vollmer, P. Vannerem, R. Vértesi, M. Verzocchi, H. Voss, J. Vossebeld, 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, G. Wolf, T. R. Wyatt, S. Yamashita, D. Zer-Zion, L. Zivkovic

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9 Citations (Scopus)


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- → νν̄γγ (γ). No evidence for new physics contributions to this final state is observed. Upper limits on σ(e+e- → XX)·BR2(X → Yγ) 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 = χ̃ 20, Y = χ̃10) and to supersymmetric models in which X=χ̃10 and Y=G̃ is a light gravitino.

Original languageEnglish
Pages (from-to)167-179
Number of pages13
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number3-4
Publication statusPublished - 2004 Nov 25

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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    Abbiendi, G., Ainsley, C., Akesson, P. F., Alexander, G., Allison, J., Amaral, P., Anagnostou, G., Anderson, K. J., Arcelli, S., Asai, S., Axen, D., Azuelos, G., Bailey, I., Barberio, E., Barillari, T., Barlow, R. J., Batley, R. J., Bechtle, P., Behnke, T., ... Zivkovic, L. (2004). Multi-photon events with large missing energy in e+e- collisions at √s = 192-209 GeV. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 602(3-4), 167-179.