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., A., Agnello, M., F., B., G., B., A., B., P., B., E., B., T., B., M., B., M. P., B., L., B., D., C., M., C., B., C., P., C., C., C., S., C., S., D.C., Denisov, O.Y.u., D., D., et al.. - 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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