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MEASUREMENTS OF THE (P)OVER-BAR-D ANNIHILATION AT REST

Authors

ABLEEV VG AGNELLO M BALESTRA F BENDISCIOLI G BERTIN A BOCCACCIO P BOTTA E BRESSANI T BRUSCHI M BUSSA MP BUSSO L CALVO D CAPPONI M CEREDA B CERELLO P CICALO C COSTA S DECASTRO S DENISOV OY DISEP D DONZELLA A FAVA L FELICIELLO A FERRERO L FILIPPI A FILIPPINI V FONTANA A GALLI D GARFAGNINI R GASTALDI U GIACOBBE B GIANOTTI P GORCHAKOV OE GRASSO A GUARALDO C IAZZI F LANARO A RIZZINI EL LOMBARDI M LUCHERINI V MAGGIORA A MANEVA G MARCELLO S MARCONI U MARGAGLIOTTI GV MARON G MASONI A MINETTI B MONTAGNA P MORANDO M NICHITIU F PANZIERI D PAULI G PICCININI M POLI M PRAKHOV SN PUDDU G RICCI RA ROSSETTO E ROTONDI A ROSHDESTVENSKY AM SAINO A SALVINI P SANTI L SAPOZHNIKOV MG SEMPRINICESARI N SERCI S SPIGHI R TEMNIKOV PP TESSARO S TOSELLO F TRETYAK VI USAI G VANNUCCI L VECCHI S VEDOVATO G VENTURELLI L VILLA M VITALE A ZENONI A ZOCCOLI A ZOSI G

Citation

Vg. Ableev et al., MEASUREMENTS OF THE (P)OVER-BAR-D ANNIHILATION AT REST, Nuclear physics. A, 585(4), 1995, pp. 577-617

Citations number

Categorie Soggetti

Physics, Nuclear

Journal title

Nuclear physics. A → ACNP

ISSN journal

03759474

Volume

585

Issue

Year of publication

1995

Pages

577 - 617

Database

ISI

SICI code

0375-9474(1995)585:4<577:MOT(AA>2.0.ZU;2-J

Abstract

The measurement of different reactions of (p) over bar d annihilation at rest in a gaseous target has been performed using the OBELIX spectr ometer at LEAR (CERN). A strong deviation from the OZI-rule prediction was found from the measurement of the ratio R = phi pi/omega pi in tw o regions of proton momenta, P < 200 MeV/c and P > 400 MeV/c: R(phi pi (-)/omega pi(-)) = (133 +/- 26) x 10(-3) and (113 +/- 30)x 10(-3), res pectively. These values are about 30 times greater than the theoretica l prediction. For the first time the excitation of the Delta-resonance was observed among the final-state products of (p) over bar d annihil ation. The existence of a broad enhancement in the 4 pi invariant mass at m approximate to 1480 MeV, seen in previous experiments, was confi rmed. A approximate to 100 MeV downward shift of the bump position, wh en the proton momentum increased up to P > 400 MeV/c, was also observe d, while the positions of omega, rho and f(2)(1270) did not change wit h the proton momentum. The following branching ratios were measured: B R((p) over bar d --> pi(-)phi p) = (6.62 +/- 0.49) X 10(-4), for P < 2 00 MeV/c; BR((p) over bar d --> pi-phi p) = (0.95 +/- 0.22) X 10(-4), for P > 400 MeV/c; BR((P) over bar d --> pi(-)omega p) = (49.7 +/- 8.9 ) X 10(-4), for P < 200 MeV/c; BR((P) over bar d --> 2 pi(-)omega p) = (8.38 +/- 1.09) X 10(-4) for P > 400 MeV/c; BR((p) over bar d --> 2 p i(-)pi(+)p) = (150 +/- 6) X 10(-4) for P < 200 MeV/c; BR((p) over bar d --> 2 pi(-)pi(+)p) = (16.6 +/- 0.9) X 10(-4), for P > 400 MeV/c; BR( (p) over bar d --> 3 pi(-)2 pi(+)p) = (326 +/- 12) X 10(-4), for P < 2 00 MeV/c; BR((p) over bar d --> 3 pi(-)2 pi(+)p) = (44 +/- 7)x 10(-4), for P > 400 MeV/c; BR((p) over bar d --> Lambda K(+)pi(-)) = (0.96 +/ - 0.19) x 10(-4), for P > 400 MeV/c; BR((p) over bar d --> Lambda K(+) pi(-)pi(0)) = (3.5 +/- 0.8) X 10(-4), for P > 400 MeV/c; BR((p) over b ar p --> 2 pi(-)2 pi(+)) = (540 +/- 20) X 10(-4); BR((p) over bar p -- > 3 pi(-)3 pi(+)) = (251 +/- 21) X 10(-4).