A data sample corresponding to almost two million hadronic Z decays collected by the ALEPH detector at LEP has been searched for monojet events. Three events were found, in agreement with the expectation from the process e+e- --> gamma*nunuBAR, with gamma* --> ffBAR. Two events are hadronic, the third one being an e+e- pair. All monojet masses are in excess of 3 GeV/c2, and two of the events have large transverse momenta: 18.5 and 20.3 GeV/c. These kinematic characteristics are quite unlikely in the process e+e- --> gamma*nunuBAR. The probability of their occurrence increases substantially when processes involving further Z or W exchanges are taken into account, but still remains at the 5% level.

Observation of monojet events and tentative interpretation / D. Buskulic, D. Casper, I. Debonis, D. Decamp, P. Ghez, C. Goy, J. Lees, M. Minard, P. Odier, B. Pietrzyk, F. Ariztizabal, M. Chmeissani, J. Crespo, I. Efthymiopoulos, E. Fernandez, M. Fernandezbosman, V. Gaitan, L. Garrido, M. Martinez, T. Mattison, S. Orteu, A. Pacheco, C. Padilla, F. Palla, A. Pascual, J. Perlas, F. Teubert, D. Creanza, M. Depalma, A. Farilla, G. Iaselli, G. Maggi, N. Marinelli, S. Natali, S. Nuzzo, A. Ranieri, G. Raso, F. Romano, F. Ruggieri, G. Selvaggi, L. Silvestris, P. Tempesta, G. Zito, Y. Chai, D. Huang, X. Huang, J. Lin, T. Wang, Y. Xie, D. Xu, R. Xu, J. Zhang, L. Zhang, W. Zhao, G. Bonvicini, J. Boudreau, P. Comas, P. Coyle, H. Drevermann, A. Engelhardt, L. Foa, R. Forty, G. Ganis, C. Gay, M. Girone, R. Hagelberg, J. Harvey, R. Jacobsen, B. Jost, J. Knobloch, I. Lehraus, M. Maggi, C. Markou, E. Martin, P. Mato, H. Meinhard, A. Minten, R. Miquel, P. Palazzi, J. Pater, P. Perrodo, J. Pusztaszeri, F. Ranjard, L. Rolandi, J. Rothberg, M. Saich, D. Schlatter, M. Schmelling, W. Tejessy, I. Tomalin, R. Veenhof, A. Venturi, H. Wachsmuth, S. Wasserbaech, W. Wiedenmann, T. Wildish, W. Witzeling, J. Wotschack, Z. Ajaltouni, M. Bardadinotwinowska, A. Barres, C. Boyer, A. Falvard, P. Gay, C. Guicheney, P. Henrard, J. Jousset, B. Michel, J. Montret, D. Pallin, P. Perret, F. Podlyski, J. Proriol, F. Saadi, T. Fearnley, J. Hansen, J. Hansen, J. Hansen, P. Hansen, S. Johnson, R. Mollerud, B. Nilsson, A. Kyriakis, E. Simopoulou, I. Siotis, A. Vayaki, K. Zachariadou, A. Blondel, G. Bonneaud, J. Brient, P. Bourdon, L. Passalacqua, A. Rouge, M. Rumpf, R. Tanaka, A. Valassi, M. Verderi, H. Videau, D. Candlin, M. Parsons, E. Veitch, E. Focardi, G. Parrini, M. Corden, M. Delfino, C. Georgiopoulos, D. Jaffe, D. Levinthal, A. Antonelli, G. Bencivenni, G. Bologna, F. Bossi, P. Campana, G. Capon, F. Cerutti, V. Chiarella, G. Felici, P. Laurelli, G. Mannocchi, F. Murtas, G. Murtas, M. Pepealtarelli, S. Salomone, P. Colrain, I. Tenhave, I. Knowles, J. Lynch, W. Maitland, W. Morton, C. Raine, P. Reeves, J. Scarr, K. Smith, M. Smith, A. Thompson, S. Thorn, R. Turnbull, U. Becker, O. Braun, C. Geweniger, P. Hanke, V. Hepp, E. Kluge, A. Putzer, B. Rensch, M. Schmidt, H. Stenzel, K. Tittel, M. Wunsch, R. Beuselinck, D. Binnie, W. Cameron, M. Cattaneo, D. Colling, P. Dornan, J. Hassard, N. Konstantinidis, L. Moneta, A. Moutoussi, J. Nash, D. Payne, G. Sanmartin, J. Sedgbeer, A. Wright, P. Girtler, D. Kuhn, G. Rudolph, R. Vogl, C. Bowdery, T. Brodbeck, A. Finch, F. Foster, G. Hughes, D. Jackson, N. Keemer, M. Nuttall, A. Patel, T. Sloan, S. Snow, E. Whelan, A. Galla, A. Greene, K. Kleinknecht, J. Raab, B. Renk, H. Sander, H. Schmidt, S. Walther, R. Wanke, B. Wolf, A. Bencheikh, C. Benchouk, A. Bonissent, D. Calvet, J. Carr, C. Diaconu, F. Etienne, D. Nicod, P. Payre, L. Roos, D. Rousseau, P. Schwemling, M. Talby, I. Abt, S. Adlung, R. Assmann, C. Bauer, W. Blum, D. Brown, P. Cattaneo, B. Dehning, H. Dietl, F. Dydak, M. Frank, A. Halley, K. Jakobs, H. Kroha, J. Lauber, G. Lutjens, G. Lutz, W. Manner, H. Moser, R. Richter, J. Schroder, A. Schwarz, R. Settles, H. Seywerd, U. Stierlin, U. Stiegler, R. Stdenis, G. Wolf, R. Alemany, J. Boucrot, O. Callot, A. Cordier, F. Courault, M. Davier, L. Duflot, J. Grivaz, P. Heusse, M. Jacquet, P. Janot, D. Kim, F. Lediberder, J. Lefrancois, A. Lutz, G. Musolino, I. Nikolic, H. Park, I. Park, M. Schune, S. Simion, J. Veillet, I. Videau, D. Abbaneo, G. Bagliesi, G. Batignani, U. Bottigli, C. Bozzi, G. Calderini, M. Carpinelli, M. Ciocci, V. Ciulli, R. Dellorso, I. Ferrante, F. Fidecaro, F. Forti, A. Giassi, M. Giorgi, A. Gregorio, F. Ligabue, A. Lusiani, P. Marrocchesi, A. Messineo, G. Rizzo, G. Sanguinetti, P. Spagnolo, J. Steinberger, R. Tenchini, G. Tonelli, G. Triggiani, C. Vannini, P. Verdini, J. Walsh, A. Betteridge, Y. Gao, M. Green, D. Johnson, P. March, T. Medcalf, L. Mir, I. Quazi, J. Strong, V. Bertin, D. Botterill, R. Clifft, T. Edgecock, S. Haywood, M. Edwards, P. Norton, J. Thompson, B. Blochdevaux, P. Colas, H. Duarte, S. Emery, W. Kozanecki, E. Lancon, M. Lemaire, E. Locci, B. Marx, P. Perez, J. Rander, J. Renardy, A. Rosowsky, A. Roussarie, J. Schuller, J. Schwindling, D. Mohand, B. Vallage, R. Johnson, A. Litke, G. Taylor, J. Wear, A. Beddall, C. Booth, S. Cartwright, F. Combley, I. Dawson, A. Koksal, C. Rankin, L. Thompson, A. Bohrer, S. Brandt, G. Cowan, E. Feigl, C. Grupen, G. Lutters, J. Minguetrodriguez, F. Rivera, P. Saraiva, U. Schafer, L. Smolik, L. Bosisio, R. Dellamarina, G. Giannini, B. Gobbo, L. Pitis, F. Ragusa, L. Bellantoni, J. Conway, Z. Feng, D. Ferguson, Y. Gao, J. Grahl, J. Harton, O. Hayes, H. Hu, J. Nachtman, Y. Pan, Y. Saadi, M. Schmitt, I. Scott, V. Sharma, J. Turk, A. Walsh, F. Weber, S. Wu, X. Wu, J. Yamartino, M. Zheng, G. Zobernig. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - 334:1/2(1994), pp. 244-252. [10.1016/0370-2693(94)90619-X]

Observation of monojet events and tentative interpretation

F. Ragusa;
1994

Abstract

A data sample corresponding to almost two million hadronic Z decays collected by the ALEPH detector at LEP has been searched for monojet events. Three events were found, in agreement with the expectation from the process e+e- --> gamma*nunuBAR, with gamma* --> ffBAR. Two events are hadronic, the third one being an e+e- pair. All monojet masses are in excess of 3 GeV/c2, and two of the events have large transverse momenta: 18.5 and 20.3 GeV/c. These kinematic characteristics are quite unlikely in the process e+e- --> gamma*nunuBAR. The probability of their occurrence increases substantially when processes involving further Z or W exchanges are taken into account, but still remains at the 5% level.
Settore FIS/01 - Fisica Sperimentale
Settore FIS/04 - Fisica Nucleare e Subnucleare
1994
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/178339
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