New data on Δ++-baryon production in annihilation at rest

Autor: A. Bertin, M. Bruschi, M. Capponi, A. Collamati, S. De Castro, R. Donà, A. Ferretti, D. Galli, B. Giacobbe, U. Marconi, M. Piccinini, M. Poli, N. Semprini Cesari, R. Spighi, S. Vecchi, A. Vezzani, F. Vigotti, M. Villa, A. Vitale, A. Zoccoli, M. Corradini, A. Donzella, E. Lodi Rizzini, L. Venturelli, A. Zenoni, C. Cicalò, A. Masoni, G. Puddu, S. Serci, P. Temnikov, G. Usai, O. Gortchakov, S. Prakhov, A. Rozhdestvensky, M. Sapozhnikov, V. Tretyak, P. Gianotti, C. Guaraldo, A. Lanaro, V. Lucherini, F. Nichitiu, C. Petrascu, A. Rosca, V. Ableev, C. Cavion, U. Gastaldi, M. Lombardi, G. Maron, L. Vannucci, G. Vedovato, G. Bendiscioli, V. Filippini, A. Fontana, P. Montagna, A. Rotondi, A. Saino, P. Salvini, C. Scoglio, F. Balestra, E. Botta, T. Bressani, M.P. Bussa, L. Busso, D. Calvo, P. Cerello, S. Costa, O. Denisov, L. Fava, A. Feliciello, L. Ferrero, A. Filippi, R. Garfagnini, A. Grasso, A. Maggiora, S. Marcello, D. Panzieri, D. Parena, E. Rossetto, F. Tosello, L. Valacca, G. Zosi, M. Agnello, F. Iazzi, B. Minetti, G. Pauli, S. Tessaro, L. Santi
Rok vydání: 1997
Předmět:
Zdroj: Physics Letters B. 403:177-184
ISSN: 0370-2693
Popis: New experimental results on p d annihilation at rest into pions plus a high momentum proton in the final state are discussed. The data sample was collected using the OBELIX spectrometer at the LEAR facility (CERN). The annihilation probabilities, or more precisely the yields (Y) via channels p d → 2π − π + π 0 p and p d → 3π − 2π + π 0 p with proton momenta p > 400 MeV/c have been measured for the first time: Y = (93.2 ± 1.6) × 10−4 and Y = (52.2 ± 1.4) × 10−4, respectively. The signal in the invariant mass distribution of the pπ+ system in the region of the well-known Δ++(1232)-isobar is clearly seen in reactions p d → 2π − π + p , p d → 2π − π + π 0 p , p d → 3π − 2π + p and p d → 3π − 2π + π 0 p . The upper limit on reaction p (Δ − Δ ++ ) → 2π − π + p in the p d annihilation at rest, which could be interpreted as a manifestation of the ΔΔ component of the deuteron, was found to be Y ≤ 6.5 × 10−5 with a 90% confidence level.
Databáze: OpenAIRE