Archivio Istituzionale della RicercaThe measurement of different reactions of d annihilation at rest in a gaseous target has been performed using the OBELIX spectrometer at LEAR (CERN). A strong deviation from the OZI-rule prediction was found from the measurement of the ratio in two regions of proton momenta, P < 200 MeV/c and P > 400 MeV/c: and (113 ± 30) × 10−3, respectively. These values are about 30 times greater than the theoretical prediction. For the first time the excitation of the †-resonance was observed among the final-state products of d annihilation. The existence of a broad enhancement in the 4π invariant mass at m ≈ 1480 MeV, seen in previous experiments, was confirmed. A ≈ 100 MeV downward shift of the bump position, when the proton momentum increased up to P > 400 MeV/c, was also observed, while the positions of ω, ϱ and f2(1270) did not change with the proton momentum. The following branching ratios were measured: ...
Measurements of the anti-p d annihilation at rest / V. G., Ableev; Agnello, Michelangelo; F., Balestra; G., Bendiscioli; A., Bertin; P., Boccaccio; E., Botta; T., Bressani; M., Bruschi; M. P., Bussa; L., Busso; D., Calvo; M., Capponi; B., Cereda; P., Cerello; C., Cicaló; S., Costa; S., De Castro; Denisov, O. Y. u.; D., 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; G., Maneva; S., Marcello; U., Marconi; G. V., Margagliotti; G., Maron; A., Masoni; Minetti, Bruno; P., Montagna; M., Morando; F., Nichitiu; D., Panzieri; G., Pauli; M., Piccinini; M., Poli; S. N., Prakhov; G., Puddu; R. A., Ricci; E., Rossetto; A., Rotondi; A. M., Roshdestvensky; A., Saino; P., Salvini; L., Santi; M. G., Sapozhnikov; N., Semprini Cesari; S., Serci; R., Spighi; P. P., Temnikov; S., Tessaro; F., Tosello; V. I., Tretyak; G., Usai; L., Vannucci; S., Vecchi; G., Vedovato; L., Venturelli; M., Villa; A., Vitale; A., Zenoni; A., Zoccoli; G., Zosi. - In: NUCLEAR PHYSICS. A. - ISSN 0375-9474. - 585:4(1995), pp. 577-617. [10.1016/0375-9474(94)00523-P]
Measurements of the anti-p d annihilation at rest
AGNELLO, MICHELANGELO;IAZZI, Felice;MINETTI, Bruno;
1995
Abstract
The measurement of different reactions of d annihilation at rest in a gaseous target has been performed using the OBELIX spectrometer at LEAR (CERN). A strong deviation from the OZI-rule prediction was found from the measurement of the ratio in two regions of proton momenta, P < 200 MeV/c and P > 400 MeV/c: and (113 ± 30) × 10−3, respectively. These values are about 30 times greater than the theoretical prediction. For the first time the excitation of the †-resonance was observed among the final-state products of d annihilation. The existence of a broad enhancement in the 4π invariant mass at m ≈ 1480 MeV, seen in previous experiments, was confirmed. A ≈ 100 MeV downward shift of the bump position, when the proton momentum increased up to P > 400 MeV/c, was also observed, while the positions of ω, ϱ and f2(1270) did not change with the proton momentum. The following branching ratios were measured: ...
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https://hdl.handle.net/11583/1845571
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