A direct measurement of the invisible width of the Z from single photon counting

D. Buskulic*, I. De Bonis, D. Decamp, P. Ghez, C. Goy, J. P. Lees, M. N. Minard, B. Pietrzyk, F. Ariztizabal, P. Comas, J. M. Crespo, M. Delfino, I. Efthymiopoulos, E. Fernandez, M. Fernandez-Bosman, V. Gaitan, Ll Garrido, T. Mattison, A. Pacheco, C. PadillaA. Pasual, D. Creanza, M. de Palma, A. Farilla, G. Iaselli, G. Maggi, S. Natali, S. Nuzzo, M. Quattromini, A. Ranieri, G. Raso, F. Romano, F. Ruggieri, G. Selvaggi, L. Silvestris, P. Tempesta, G. Zito, Y. Chai, H. Hu, D. Huang, X. Huang, J. Lin, T. Wang, Y. Xie, D. Xu, R. Xu, J. Zhang, L. Zhang, W. Zhao, E. Blucher, G. Bonvicini, J. Boudreau, D. Casper, H. Drevermann, R. W. Forty, G. Ganis, C. Gay, R. Hagelberg, J. Harvey, J. Hilgart, R. Jacobsen, B. Jost, J. Knobloch, I. Lehraus, T. Lohse, M. Maggi, C. Markou, M. Martinez, P. Mato, H. Meinhard, A. Minten, A. Miotto, R. Miquel, H. G. Moser, P. Palazzi, J. R. Pater, J. A. Perlas, J. F. Pusztaszeri, F. Ranjard, G. Redlinger, L. Rolandi, J. Rothberg, T. Ruan, M. Saich, D. Schlatter, M. Schmelling, F. Sefkow, W. Tejessy, I. R. Tomalin, R. Veenhof, H. Wachsmuth, S. Wasserbaech, W. Wiedenmann, T. Wildish, W. Witzeling, J. Wotschack, Z. Atjaltouni, F. Badaud, M. Bardadin-Otwinowska, R. El Fellous, A. Falvard, P. Gay, C. Guicheney, P. Henrard, J. Jousset, B. Michel, J. C. Montret, D. Pallin, P. Perret, F. Podlyski, J. Proriol, F. Prulhière, F. Saadi, T. Fearnley, J. B. Hansen, J. D. Hansen, J. R. Hansen, P. H. Hansen, R. Møllerud, B. S. Nilsson, A. Kyriakis, E. Simopoulou, I. Siotis, A. Vayaki, K. Zachariadou, J. Badier, A. Blondel, G. Bonneaud, J. C. Brient, G. Fouque, S. Orteu, A. Rougé, M. Rumpf, R. Tanaka, M. Verderi, H. Videau, D. J. Candlin, M. I. Parsons, E. Veitch, E. Focardi, L. Moneta, G. Parrini, M. Corden, C. Georgiopoulos, M. Ikeda, D. Levinthal, A. Antonelli, R. Baldini, G. Bencivenni, G. Bologna, F. Bossi, P. Campana, G. Capon, F. Cerutti, V. Chiarella, B. D'Ettorre-Piazzoli, G. Felici, P. Laurelli, G. Mannocchi, F. Murtas, G. P. Murtas, L. Passalacqua, M. Pepe-Altarelli, P. Picchi, P. Colrain, I. ten Have, J. G. Lynch, W. Maitland, W. T. Morton, C. Raine, P. Reeves, J. M. Scarr, K. Smith, M. G. Smith, A. S. Thompson, R. M. Turnbull, B. Brandl, O. Braun, C. Geweniger, P. Hanke, V. Hepp, E. E. Kluge, Y. Maumary, A. Putzer, B. Rensch, A. Stahl, K. Tittel, M. Wunsch, R. Beuselinck, D. M. Binnie, W. Cameron, M. Cattaneo, D. J. Colling, P. J. Dornan, A. M. Greene, J. F. Hassard, N. M. Lieske, A. Moutoussi, J. Nash, S. Patton, D. G. Payne, M. J. Phillips, G. San Martin, J. K. Sedgbeer, A. G. Wright, P. Girtler, D. Kuhn, G. Rudolph, R. Vogl, C. K. Bowdery, T. J. Brodbeck, A. J. Finch, F. Foster, G. Hughes, D. Jackson, N. R. Keemer, M. Nuttall, A. Petl, T. Sloan, S. W. Snow, E. P. Whelan, K. Kleinknecht, J. Raab, B. Renk, H. G. Sander, H. Schmidt, F. Steeg, S. M. Walther, R. Wanke, B. Wolf, A. M. Bencheikh, C. Benchouk, A. Bonissent, J. Carr, P. Coyle, J. Drinkard, F. Etienne, D. Nicod, S. Papalexiou, P. Payre, L. Roos, D. Rousseau, P. Schwemling, M. Talby, S. Adlung, R. Assmann, C. Bauer, W. Blum, D. Brown, P. Cattaneo, B. Dehning, H. Dietl, F. Dydak, M. Frank, A. W. Halley, K. Jakobs, J. Lauber, G. Lütjens, G. Lutz, W. Männer, R. Richter, J. Schröder, A. S. Schwarz, R. Settles, H. Seywerd, U. Stielin, U. Stiegler, R. St. Denis, G. Wolf, R. Alemany, J. Boucrot, O. Callot, A. Cordier, M. Davier, L. Duflot, J. F. Grivaz, Ph Heusse, D. E. Jaffe, P. Janot, D. W. Kim, F. Le Diberder, J. Lefrançois, A. M. Lutz, M. H. Schune, J. J. Veillet, I. Videau, Z. Zhang, D. Abbaneo, G. Bagliesi, G. Batignani, U. Bottigli, C. Bozzi, G. Calderini, M. Carpinelli, M. A. Ciocci, V. Ciulli, R. Dell'Orso, I. Ferrante, F. Fidecaro, L. Foà, F. Forti, A. Giassi, M. A. Giorgi, A. Gregorio, F. Ligabue, A. Lusiani, E. B. Mannelli, P. S. Marrocchesi, A. Messineo, F. Palla, G. Sanguinetti, P. Spagnolo, J. Steinberger, R. Tenchini, G. Tonelli, G. Triggiani, A. Valassi, C. Vannini, A. Venturi, P. G. Verdini, J. Walsh, A. P. Betteridge, Y. Gao, M. G. Green, P. V. March, Ll M. Mir, T. Medcalf, I. S. Quazi, J. A. Strong, L. R. West, D. R. Botteril, R. W. Clifft, T. R. Edgecock, S. Haywood, P. R. Norton, J. C. Thompson, B. Bloch-Devaux, P. Colas, H. Duarte, S. Emery, W. Kozanecki, E. Lançon, M. C. Lemaire, E. Locci, B. Marx, P. Perez, J. Rander, J. F. Renardy, A. Rosowsky, A. Roussarie, J. P. Schuller, J. Schwindling, D. Si Mohand, B. Vallage, R. P. Johnson, A. M. Litke, G. Taylor, J. Wear, J. G. Ashman, W. Babbage, C. N. Booth, C. Buttar, S. Cartwright, F. Combley, I. Dawson, L. F. Thompson, E. Barberio, A. Böhrer, S. Brandt, G. Cowan, C. Grupen, G. Lutters, F. Rivera, U. Schäfer, L. Smolik, L. Bosisio, R. Della Marina, G. Giannini, B. Gobbo, F. Ragusa, L. Bellatoni, W. Chen, J. S. Conway, Z. Feng, D. P S Ferguson, Y. S. Gao, J. Grahl, J. L. Harton, O. J. Hayes, J. M. Nachtman, Y. B. Pan, Y. Saadi, M. Schmitt, I. Scott, V. Sharma, Z. H. Shi, J. D. Turk, A. M. Walsh, F. V. Weber, Lan Wu Sau Lan Wu, X. Wu, M. Zheng, G. Zobernig

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

50 Scopus citations

Abstract

The ALEPH detector at LEP is used to study single photon events in e+e- collisions at the Z resonance. In a total data sample of 15.7 pb-1 taken in 1990 and 1991 scanning the resonance, 400 events were recorded where each has a single deposition of more than 1.5 GeV measured in the polar angular region | cosθγ | < 0.74 of the electromagnetic calorimeter. It is shown that this number of events cab be accounted for by known processes. After subtraction of background events, the invisible width of the Z is determined to be 45 ± 34(stat.) ± 34(syst.) MeV. Using Z. resonance parameters derived by ALEPH, the corresponding number oflight neutrino generations is found to be 2.68 ± 0.20(stat.) ± 0.20(syst.).

Original languageEnglish (US)
Pages (from-to)520-534
Number of pages15
JournalPhysics Letters B
Volume313
Issue number3-4
DOIs
StatePublished - Sep 2 1993

Funding

8 Supported by the National Science Foundation of China. 17 Supported by the Direction des Sciences de la Mati~re, CEA. 19 Supported by the Korean Science and Engineering Foun-dation and Ministry of Education. l0 Supported by the UK Science and Engineering Research Council. 18 Supported by the Fonds zur F6rderung der wis-senschaftlichen Forschung, Austria. 13 Supported by the NSF, contract PHY-8451274. 9 Supported by the Danish Natural Science Research Council. 12 Supported by the US Department of Energy, contract DE-FG05-87ER40319. 7 Supported by CICYT, Spain. zz Supported by the US Department of Energy, contract DE-AC02-76ER00881. 16 Supported by the Bundesministerium fiir Forschung und 25 Supported by the US Department of Energy, grant DE-FG03-92ER40689.

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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