1. New results on a search for a 33.9 MeV/c2 neutral particle from π+ decay in the NOMAD experiment
- Author
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T. Weisse, J.-P. Mendiburu, K. Benslama, H. Zaccone, Alessandro Cardini, H. Pessard, Marco Fraternali, P. Rathouit, C. Joseph, Fr Pastore, B. A. Popov, P. Hurst, V. Flaminio, M. T. Tran, C. Lachaud, F. J. P. Soler, L. Di Lella, Giacomo Graziani, G. Bassompierre, S. Boyd, M. Valdata-Nappi, Marco Laveder, J.M. Gaillard, Roberto Ferrari, B. Lakić, G. N. Taylor, D. Steele, E. Gangler, J. Dumarchez, M. C. Gonzalez-Garcia, K. Schahmaneche, F. Juget, J. A. Hernando, Malcolm Ellis, M. Kirsanov, Th. Stolarczyk, A.-M. Touchard, O. Klimov, R. Cousins, Bruce Yabsley, J.J. Gómez-Cadenas, X. Méchain, J. Rico, A. Marchionni, J.-M. Vieira, Valerio Vercesi, A. Cervera-Villanueva, M. E. Sevior, Dmitry V. Naumov, Kevin Varvell, C. Nguyen-Mau, A. Placci, L. Camilleri, R. Petti, Stefano Lacaprara, A. Kovzelev, Fergus Wilson, T. Del Prete, Caroline Poulsen, E. do Couto e Silva, F. Salvatore, Vyacheslav Valuev, A. De Santo, E. Pennacchio, N. Hyett, S.A. Bunyatov, J. Bouchez, F. Vannucci, M. Gouanère, H. Degaudenzi, G. J. Feldman, J-P. Meyer, S. N. Tovey, I. Bird, A. Lupi, G. F. Moorhead, A. Grant, D. Hubbard, P. Zuccon, J.-M. Levy, G. Collazuol, Mario Stipčević, Didier Ferrere, G. Conforto, Barry Blumenfeld, L.J. Winton, A. Baldisseri, Claus Gößling, J. Kokkonen, G. Vidal-Sitjes, Sergei Gninenko, A. Krasnoperov, P. Nédélec, M. Mezzetto, T. Vinogradova, Nathalie Besson, D. Sillou, J. Ulrichs, Kai Zuber, E. Tsesmelis, Caren Hagner, T. Fazio, André Rubbia, A. Godley, G. Sozzi, A. Guglielmi, S.R. Mishra, Chiara Roda, L. Linssen, D. Pollmann, E. Iacopini, P. Astier, D. Autiero, F.V. Weber, A. Letessier-Selvon, D. Daniels, Giacomo Polesello, M. Tareb-Reyes, Vincenzo Cavasinni, J. Long, Domizia Orestano, F. Martelli, M. Contalbrigo, T. Dignan, U. Stiegler, A. Lanza, J. Gosset, D. Gibin, A. Polyarush, Achim Geiser, L. S. Peak, M. Veltri, Antonio Bueno, A. N. Toropin, L. La Rotonda, M. Baldo-Ceolin, M. Banner, D. Geppert, P.W. Cattaneo, Ante Ljubičić, F. Bobisut, N.V. Krasnikov, C. Conta, B. Schmidt, Yu. Nefedov, L. Vacavant, and V. Tereshchenko
- Subjects
Physics ,Nuclear and High Energy Physics ,Particle physics ,Neutrino decay ,Neutrino mixing ,Branching fraction ,Nuclear physics ,Pion ,Pi ,Direct search ,Anomaly (physics) ,Neutral particle ,Event (particle physics) ,KARMEN - Abstract
We report on a direct search in NOMAD for a new 33.9 MeV/c^2 neutral particle (X) produced in pion decay in flight, pi-->mu_X followed by the decay X -->nu e^+e^-. Both decays are postulated to occur to explain the time anomaly observed by the KARMEN experiment. From the analysis of the data collected during the 1996?1998 runs with 4.1×10^19 protons on target, a single candidate event consistent with background expectations was found. The search is sensitive to a pion branching ratio BR(pi-->muX >3.7×10^-15, significantly smaller than previous experimental limits.
- Published
- 2002