Archivio Istituzionale della RicercaData 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 and have been studied. The analysis of the angular distribution of the kaons emitted by the φ decay has shown that the reaction occurs essentially from 3S1 states with a production rate RNTP = (2.46 ± 0.23 ± 0.07) × 10−4, while the rate from 1P1 states is compatible with zero. Because of acceptance limitations, 3S1 and 1P1 contributions to the reaction could not be resolved and lower and upper limits for the production rate have been measured with the middle value RNTP = (0.87 ± 0.21) × 10−4. Also, for the phase-space K+K−η events the production rate RNTP = (4.67 ± 0.35) × 10−4 has been measured. The φπ0 and φη branching ratios in S- and P-waves (defined in the text) have been estimated in a model dependent way. For the evaluation of the φη rate, a combination of our production rate and of data obtained with a liquid target has been used. The φπ0 production rate, compared to our preliminary value for the ωπ0 production, confirms the strong violation of the OZI rule observed in other experiments. No violation is apparent in the φη production.
φπ0 and φη production in antiproton annihilation at rest in a hydrogen gas target at NTP / V. G., Ableev; Agnello, Michelangelo; F., Balestra; G., Bendiscioli; S., Bergamaschi; A., Bertin; E., Botta; T., Bressani; M., Bruschi; M. P., Bussa; L., Busso; D., Calvo; M., Capponi; C., Cavion; B., Cereda; P., Cerello; C., Cicalò; M., Corradini; S., Costa; S., De Castro; Denisov, O. Y. u.; F., D'Isep; A., Donzella; L., Fava; A., Feliciello; L., Ferrero; A., Filippi; V., Filippini; A., Fontana; D., Galli; R., Garfagnini; U., Gastaldi; B., Giacobbe; P., Gianotti; O. E., Gorchakov; A., Grasso; C., Guaraldo; Iazzi, Felice; A., Lanaro; E., Lodi Rizzini; M., Lombardi; V., Lucherini; A., Maggiora; S., Marcello; U., Marconi; G. V., Margagliotti; A., Masoni; Minetti, Bruno; P., Montagna; M., Morando; F., Nichitiu; D., Panzieri; D., Parena; P., Pauli; C., Petrascu; M., Piccinini; S., Prakhov; G., Puddu; A., Rosca; E., Rossetto; A., Rotondi; A. M., Rozhdenstvensky; A., Saino; P., Salvini; L., Santi; M. G., Sapozhnikov; C., Scoglio; N., Semprini Cesari; S., Serci; R., Spighi; P., Temnikov; S., Tessaro; F., Tosello; V. I., Tretyak; G. L., Usai; L., Vannucci; S., Vecchi; G., Vedovato; L., Venturelli; M., Villa; A., Vitale; A., Zenoni; A., Zoccoli. - In: NUCLEAR PHYSICS. A. - ISSN 0375-9474. - 594:4(1995), pp. 375-405. [10.1016/0375-9474(95)00345-2]
φπ0 and φη production in antiproton annihilation at rest in a hydrogen gas target at NTP
AGNELLO, MICHELANGELO;IAZZI, Felice;MINETTI, Bruno;
1995
Abstract
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 and have been studied. The analysis of the angular distribution of the kaons emitted by the φ decay has shown that the reaction occurs essentially from 3S1 states with a production rate RNTP = (2.46 ± 0.23 ± 0.07) × 10−4, while the rate from 1P1 states is compatible with zero. Because of acceptance limitations, 3S1 and 1P1 contributions to the reaction could not be resolved and lower and upper limits for the production rate have been measured with the middle value RNTP = (0.87 ± 0.21) × 10−4. Also, for the phase-space K+K−η events the production rate RNTP = (4.67 ± 0.35) × 10−4 has been measured. The φπ0 and φη branching ratios in S- and P-waves (defined in the text) have been estimated in a model dependent way. For the evaluation of the φη rate, a combination of our production rate and of data obtained with a liquid target has been used. The φπ0 production rate, compared to our preliminary value for the ωπ0 production, confirms the strong violation of the OZI rule observed in other experiments. No violation is apparent in the φη production.
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https://hdl.handle.net/11583/1845573
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