Data di Pubblicazione:
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 R = ~b~r/to~r in
two regions of proton momenta, P < 200 MeV/c and P > 400 MeV/c: R(&~r-/toTr-) =
(133 + 26)× 10 -3 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 A-resonance
was observed among the final-state products of ~d annihilation. The existence of a broad
enhancement in the 4~r 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 to, p and
f2(1270) did not change with the proton momentum. The following branching ratios were
measured: BR(~d ~ 7r-~bp) = (6.62 + 0.49) × 10 -4, for P < 200 MeV/c; BR(pd --* zr-~bp)
= (0.95 + 0.22) × 10 -4, for P > 400 MeV/c; BR(~d ~ r-top) = (49.7 + 8.9) x 10 -4, for P
< 200 MeV/c; BR(~d ~ ~--top) = (8.38 + 1.09) × 10 -4, for P > 400 MeV/c; BR(~d --+
2~--zr+p) = (150 + 6) × 10 -4, for P < 200 MeV/c; BR(~d --* 2~--zr+p) = (16.6 + 0.9) ×
10 -4, for P > 400 MeV/c; BR(~d --* 37r-2~r+p) = (326 + 12) × 10 -4, for P < 200 MeV/c;
BR(~d --+ 37r-2~-+p) --- (44 _ 7) × 10 -4, for P > 400 MeV/c; BR(~d ---, AK+~ "-) = (0.96 +
0.19) × 10 -4, for P > 400 MeV/c; BR(pd ~ AK+~--~ "°) ---- (3.5 + 0.8) × 10 -4, for P > 400
MeV/c; BR(~p ~ 2~r-27r +) = (540 + 20) X 10-4; BR(~p --* 3~-3~ "+) = (251 + 21) x 10 -4.
Tipologia CRIS:
1.1 Articolo in rivista
Elenco autori:
V. G., Ableev a; M., Agnello c; F., Balestra d; G., Bendiscioli e; A., Bertin f; P., Boccaccio g; E., Botta d; T., Bressani d; M., Bruschi f; M. P., Bussa d; L., Busso d; D., Calvo d; M., Capponi f; B., Cereda f; P., Cerello d; C., Cical6 b; S., Costa d; S., De Castro f; Denisov a, O. Y. u.; D., D'Isep d; A., Donzella i; L., Fava d; A., Feliciello d; L., Ferrero d; A., Filippi d; V., Filippini e; Fontana, Andrea; D., Galli f; R., Garfagnini d; U., Gastaldi g; B., Giacobbe f; P., Gianotti h; O. E., Gorchakov a; A., Grasso d; C., Guaraldo h; F., Iazzi c; A., Lanaro h; E., Lodi Rizzini i; M. Lombardi g. V., Lucherini h; A., Maggiora d; G., Maneva a; S., Marcello d; U. Marconi f' G. V., Margagliotti J; G., Maron ~; A., Masoni b; B., Minetti c; Montagna, PAOLO MARIA; M., Morando k; F., Nichitiu a; H, ; D., Panzieri d; G., Pauli J; M., Piccinini f; M., Poli l; S. N., Prakhov a; G., Puddu b; R. A., Ricci g; K, ; E., Rossetto d; Rotondi, Alberto; A. M., Roshdestvensky a; A., Saino ~; P., Salvini; L., Santi m; M. G., Sapozhnikov a; N., Semprini Cesari f; S., Serci b; R., Spighi f; P. P., Temnikov b; S., Tessaro J; F., Tosello d; V. I., Tretyak a; E, ; G., Usai b; L., Vannucci g; S., Vecchi f; G., Vedovato g; L., Venturelli i; M., Villa f; A., Vitale f; A., Zenoni n; A., Zoccoli f; G., Zosi
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