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Phi pi0 and Phi eta production in anti-proton annihilation at rest in a hydrogen gas target at NTP

By V.G. Ableev a.i M. Agnello b, F. Balestra c, G. Bendiscioli e, S. Bergamaschi e, A. Bertin e E. Botta c, T. Bressani c, M. Bruschi e, M.P. Bussa c, L. Busso c, D. Calvo b, M. Capponi f C. Cavion a, B. Cereda f, P. Cerello c, C. Cical6 h, M. Corradini d ~, S. Costa c, S. De Castro e, O.Yu. Denisov g, F. D'Isep c, A. Donzella d L. Fava c, A. Feliciello c L. Ferrero c A. Filippi c V. Filippini e, A. Fontana, D. Galli ~, R. Garfagnini c, U. Gastaldi a, B. Giacobbe f, P. Gianotti i, O.E. Gorchakov g, A. Grasso c, C. Guaraldo i, F. Iazzi b, A. Lanaro i, E. Lodi Rizzini d, M. Lombardi a V. Lucherini i, A. Maggiora c, S. Marcello c, U. Marconi e, G.V. Margagliotti J, A. Masoni h, B. Minetti b, P. Montagna, M. Morando k, F. Nichitiu i, l, D. Panzieri c, D. Parena e, p. Pauli J, C. Petrascu i, 2, M. Piccinini f, S. Prakhov g, G. Puddu h, A. Rosca i, 2, E. Rossetto, A. Rotondi, A.M. Rozhdenstvensky g, A. Saino e, p. Salvini e, L. Santi 1, M.G. Sapozhnikov g, C. Scoglio e, N. Semprini Cesari f, S. Serci h, R. Spighi f, P. Temnikov h, S. Tessaro J, F. Tosello c, V.I. Tretyak g, G.L. Usai h, L. Vannucci a, S. Vecchi f, G. Vedovato a, L. Venturelli d, M. Villa f, A. Vitale f, A. Zenoni re.n and A. Zoccoli f


Data of antiproton annihilation at rest in a hydrogen gas target at NTP have been collected with the Obelix spectrometer exposed to the beam extracted from the LEAR accelerator of CERN. The reactions pbar p --> Phi pi0 and Phi Eta have been studied. The analysis of the angular distribution of the kaons emitted by the ~b decay has shown that the reaction ~p ~ ¢~" 0 occurs essentially from 3S 1 states with a production rate RrcrP = (2.46 ___ 0.23 _ 0.07) x 10 -4, while the rate from 1P 1 states is compatible with zero. Because of acceptance limitations, 3S 1 and 1p1 contributions to the reaction ~p ~ ~br/could not be resolved and lower and upper limits for the production rate have been measured with the middle value Rm. P = (0.87 + 0.21) x 10 -4. Also, for the phase-space K+K-r/ events the production rate RN~ = (4.67 ___ 0.35) × 10 -4 has been measured. The thTr ° and th*/branching ratios in S- and P-waves (defined in the text) have been estimated in a model dependent way. For the evaluation of the ~b~/ rate, a combination of our production rate and of data obtained with a liquid target has been used. The ~b~r ° production rate, compared to our preliminary value for the to~ -° production, confirms the strong violation of the OZI rule observed in other experiments. No violation is apparent in the PhiEta production

Year: 1995
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