A search is reported for decays of the Z0 into π0γ, ηγ and η′ (958)γ in e+e− collisions using data collected during a scan around the Z0 mass. In order to search for π0γ final states, in which the two photons from the π0 decay are unresolved, the production of pairs of high-energy electromagnetic clusters is studied. The data are compared with the expectations from the pure QED process e+e− → γγ, and a 95% confidence level upper limit on the branching ratio of the Z0 into π0γ of 4.9 × 10−4 is derived. For η′γ, the decay modes of the mesons that contain two charged particles are largely free from QED background. These modes are used to place upper limits of 4.6 × 10−4 and 2.2 × 10−4 on the corresponding branching ratios of the Z0.
Search for decays of the Z0 into a photon and a pseudoscalar meson / D. Decamp, B. Deschizeaux, C. Goy, J. Lees, M. Minard, J. Crespo, M. Delfino, E. Fernandez, M. Martinez, R. Miquel, L. Mir, S. Orteu, A. Pacheco, J. Perlas, E. Tubau, M. Catanesi, M. De Palma, A. Farilla, G. Iaselli, G. Maggi, S. Natali, S. Nuzzo, A. Ranieri, G. Raso, F. Romano, F. Ruggieri, G. Selvaggi, L. Silvestris, P. Tempesta, G. Zito, Y. Gao, H. Hu, D. Huang, S. Jin, J. Lin, T. Ruan, T. Wang, W. Wu, Y. Xie, D. Xu, R. Xu, J. Zhang, Z. Zhang, W. Zhao, H. Albrecht, W. Atwood, F. Bird, E. Blucher, T. Burnett, T. Charity, H. Drevermann, L. Garrido, C. Grab, R. Hagelberg, S. Haywood, B. Jost, M. Kasemann, G. Kellner, J. Knobloch, A. Lacourt, I. Lehraus, T. Lohse, D. Luke, A. Marchioro, P. Mato, J. May, A. Minten, A. Miotto, P. Palazzi, M. Pepe Altarelli, F. Ranjard, A. Roth, J. Rothberg, H. Rotscheidt, W. Vonruden, R. Stdenis, D. Schlatter, M. Takashima, M. Talby, H. Taureg, W. Tejessy, H. Wachsmuth, S. Wheeler, W. Wiedenmann, W. Witzeling, J. Wotschack, Z. Ajaltouni, M. Bardadinotwinowska, A. Falvard, P. Gay, P. Henrard, J. Jousset, B. Michel, J. Montret, D. Pallin, P. Perret, J. Proriol, F. Prulhiere, J. Hansen, J. Hansen, P. Hansen, R. Mollerud, G. Petersen, E. Simopoulou, A. Vayaki, J. Badier, A. Blondel, G. Bonneaud, J. Bourotte, F. Braems, J. Brient, M. Ciocci, G. Fouque, R. Guirlet, A. Rouge, M. Rumpf, R. Tanaka, H. Videau, I. Videau, D. Candlin, A. Conti, G. Parrini, M. Corden, C. Georgiopoulos, J. Goldman, M. Ikeda, J. Lannutti, D. Levinthal, M. Mermikides, L. Sawyer, G. Stimpfl, A. Antonelli, R. Baldini, G. Bencivenni, G. Bologna, F. Bossi, P. Campana, G. Capon, V. Chiarella, G. Deninno, B. Dettorrepiazzoli, G. Felici, P. Laurelli, G. Mannocchi, F. Murtas, G. Murtas, G. Nicoletti, P. Picchi, P. Zografou, B. Altoon, O. Boyle, A. Halley, I. Tenhave, J. Hearns, J. Lynch, W. Morton, C. Raine, J. Scarr, K. Smith, A. Thompson, B. Brandl, O. Braun, R. Geiges, C. Geweniger, P. Hanke, V. Hepp, E. Kluge, Y. Maumary, M. Panter, A. Putzer, B. Rensch, A. Stahl, K. Tittel, M. Wunsch, A. Belk, R. Beuselinck, D. Binnie, W. Cameron, M. Cattaneo, P. Dornan, S. Dugeay, R. Forty, A. Greene, J. Hassard, S. Patton, J. Sedgbeer, G. Taylor, I. Tomalin, A. Wright, P. Girtler, D. Kuhn, G. Rudolph, C. Bowdery, T. Brodbeck, A. Finch, F. Foster, G. Hughes, N. Keemer, M. Nuttall, B. Rowlingson, T. Sloan, S. Snow, T. Barczewski, L. Bauerdick, K. Kleinknecht, B. Renk, S. Roehn, H. Sander, M. Schmelling, F. Steeg, J. Albanese, J. Aubert, C. Benchouk, A. Bonissent, D. Courvoisier, F. Etienne, E. Matsinos, S. Papalexiou, P. Payre, B. Pietrzyk, Z. Qian, W. Blum, P. Cattaneo, G. Cowan, B. Dehning, H. Dietl, M. Fernandez Bosman, D. Hauff, A. Jahn, E. Lange, G. Lutjens, G. Lutz, W. Manner, H. Moser, Y. Pan, R. Richter, A. Schwarz, R. Settles, U. Stiegler, U. Stierlin, J. Thomas, G. Waltermann, V. Bertin, G. Debouard, J. Boucrot, O. Callot, X. Chen, A. Cordier, M. Davier, G. Ganis, J. Grivaz, P. Heusse, P. Janot, V. Journe, D. Kim, J. Lefrancois, A. Lutz, J. Veillet, F. Zomer, S. Amendolia, G. Bagliesi, G. Batignani, L. Bosisio, U. Bottigli, C. Bradaschia, I. Ferrante, F. Fidecaro, L. Foa, E. Focardi, F. Forti, A. Giassi, M. Giorgi, F. Ligabue, A. Lusiani, E. Mannelli, P. Marrocchesi, A. Messineo, F. Palla, G. Sanguinetti, S. Scapellato, J. Steinberger, R. Tenchini, G. Tonelli, G. Triggiani, J. Carter, M. Green, P. March, T. Medcalf, M. Saich, J. Strong, R. Thomas, T. Wildish, D. Botterill, R. Clifft, T. Edgecock, M. Edwards, S. Fisher, J. Harvey, T. Jones, P. Norton, D. Salmon, J. Thompson, B. Blochdevaux, P. Colas, C. Klopfenstein, E. Lancon, E. Locci, S. Loucatos, L. Mirabito, E. Monnier, P. Perez, F. Perrier, J. Rander, J. Renardy, A. Roussarie, J. Schuller, J. Ashman, C. Booth, F. Combley, M. Dinsdale, J. Martin, D. Parker, L. Thompson, S. Brandt, H. Burkhardt, C. Grupen, H. Meinhard, E. Neugebauer, U. Schafer, H. Seywerd, B. Gobbo, F. Liello, E. Milotti, F. Ragusa, L. Rolandi, L. Bellantoni, J. Boudreau, D. Cinabro, J. Conway, D. Cowen, Z. Feng, J. Harton, J. Hilgart, R. Jared, R. Johnson, B. Leclaire, Y. Pan, T. Parker, J. Pater, Y. Saadi, V. Sharma, J. Wear, F. Weber, S. Wu, S. Xue, G. Zobernig. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - 241:4(1990), pp. 635-643. [10.1016/0370-2693(90)91883-D]
Search for decays of the Z0 into a photon and a pseudoscalar meson
F. Ragusa;
1990
Abstract
A search is reported for decays of the Z0 into π0γ, ηγ and η′ (958)γ in e+e− collisions using data collected during a scan around the Z0 mass. In order to search for π0γ final states, in which the two photons from the π0 decay are unresolved, the production of pairs of high-energy electromagnetic clusters is studied. The data are compared with the expectations from the pure QED process e+e− → γγ, and a 95% confidence level upper limit on the branching ratio of the Z0 into π0γ of 4.9 × 10−4 is derived. For η′γ, the decay modes of the mesons that contain two charged particles are largely free from QED background. These modes are used to place upper limits of 4.6 × 10−4 and 2.2 × 10−4 on the corresponding branching ratios of the Z0.
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