1. Search for a new gauge boson in $\pi^{0}$ decays
- Author
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J. Altegoer, P. Astier, D. Autiero, A. Baldisseri, M. Baldo-Ceolin, G. Ballocchi, M. Banner, S. Basa, G. Bassompierre, K. Benslama, N. Besson, I. Bird, B. Blumenfeld, F. Bobisut, J. Bouchez, S. Boyd, A. Bueno, S. Bunyatov, L. Camilleri, A. Cardini, A. Castera, P.W. Cattaneo, V. Cavasinni, A. Cervera-Villanueva, G.M. Collazuol, G. Conforto, C. Conta, M. Contalbrigo, R. Cousins, D. Daniels, A.De Santo, T.Del Prete, T. Dignan, L.Di Lella, E. do Couto e Silva, I.J. Donnelly, J. Dumarchez, T. Fazio, G.J. Feldman, R. Ferrari, D. Ferrère, V. Flaminio, M. Fraternali, J-M. Gaillard, P. Galumian, E. Gangler, A. Geiser, D. Geppert, D. Gibin, S.N. Gninenko, J-J. Gomez-Cadenas, J. Gosset, C. Gößling, M. Gouanère, A. Grant, G. Graziani, A. Guglielmi, C. Hagner, J. Hernando, D. Hubbard, P. Hurst, N. Hyett, E. Iacopini, C. Joseph, D. Kekez, B. Khomenko, M.M. Kirsanov, O. Klimov, J. Kokkonen, A.V. Kovzelev, V. Kuznetsov, S. Lacaprara, A. Lanza, L. La Rotonda, M. Laveder, A. Letessier-Selvon, J-M. Levy, L. Linssen, A. Ljubičić, J. Long, A. Lupi, E. Manola-Poggioli, A. Marchionni, F. Martelli, X. Méchain, J-P. Mendiburu, J-P. Meyer, M. Mezzetto, S.R. Mishra, G.F. Moorhead, L. Mossuz, P. Nédélec, Yu. Nefedov, C. Nguyen-Mau, D. Orestano, F. Pastore, L.S. Peak, E. Pennacchio, J-P. Perroud, H. Pessard, R. Petti, A. Placci, H. Plothow-Besch, A. Pluquet, G. Polesello, D. Pollmann, B.G. Pope, B. Popov, C. Poulsen, P. Rathouit, C. Roda, A. Rubbia, F. Salvatore, D. Scannicchio, K. Schahmaneche, B. Schmidt, A. Sconza, M. Serrano, M.E. Sevior, D. Sillou, F.J.P. Soler, G. Sozzi, D. Steele, P. Steffen, M. Steininger, U. Stiegler, M. Stipčević, T. Stolarczyk, M. Tareb-Reyes, G.N. Taylor, S. Tereshchenko, A.N. Toropin, A-M. Touchard, S.N. Tovey, M-T. Tran, E. Tsesmelis, J. Ulrichs, V. Uros, M. Valdata-Nappi, V. Valuev, F. Vannucci, K.E. Varvell, M. Veltri, V. Vercesi, D. Verkindt, J-M. Vieira, T. Vinogradova, M-K. Vo, S.A. Volkov, F. Weber, T. Weisse, M. Werlen, F. Wilson, L.J. Winton, B.D. Yabsley, H. Zaccone, and K. Zuber
- Subjects
Physics ,Nuclear and High Energy Physics ,Gauge boson ,Particle physics ,Large Hadron Collider ,Branching fraction ,Physics::Instrumentation and Detectors ,Astrophysics::High Energy Astrophysical Phenomena ,High Energy Physics::Phenomenology ,Física ,High Energy Physics - Experiment ,Pion ,Coulomb ,High Energy Physics::Experiment ,Neutrino ,Nuclear Experiment ,Primakoff effect ,Energy (signal processing) ,Particle Physics - Experiment - Abstract
A search was made for a new light gauge boson $X$ which might be produced in $\pi^{0}\to\gamma + X$ decay from neutral pions generated by 450-GeV protons in the CERN SPS neutrino target. The X's would penetrate the downstream shielding and be observed in the NOMAD detector via the Primakoff effect, in the process of $X \to\pi^{0}$ conversion in the external Coulomb field of a nucleus. With $1.45\times10^{18}$ protons on target, 20 candidate events with energy between 8 and 140 GeV were found from the analysis of neutrino data. This number is in agreement with the expectation of 18.1$\pm$2.8 background events from standard neutrino processes. A new 90% C.L. upper limit on the branching ratio $Br(\pi^{0}\to\gamma + X)< (3.3 to 1.9) \times10^{-5}$ for $X$ masses ranging from 0 to 120 MeV/c^2 is obtained., Comment: 15 pages, LaTex, 6 eps figures included, submitted to Physics Letters B
- Published
- 1998