Published March 1980 | Version v1
Report Open

Study of Λ production in π-p interactions at 8 GeV/c and π+p interactions at 12 GeV/c

Description

At this time, few results for reactions with backwards produced mesons are available, and their interpretation is not easy. Baryon exchange mechanism is more intricate than meson exchange. The study of reactions π-p→Λav + K0 and π-p → Λav + K*0890 with 8 GeV/c incident π-, by means of Regge trajectories formalism and scattering amplitudes in u-channel, has shown that the polarization of the Λ is nearly 1 in the backward peak and that these reactions are dominated by unnatural parity exchanges; this result may be explained by the difference between octet couplings for natural and unnatural trajectories exchanges. The search for exotic meson system in the reaction π+ + p → Λav + K++ at 12 Gev/c has not led to establish the existence of such a system, but we give upper limits on their production cross sections, that we found of the same order of magnitude as those obtained for the reaction π-p → Λav + K*890, in good agreement with the two-components duality predictions

Availability note (English)

MF available from INIS under the Report Number.

Abstract (French)

A l'heure actuelle, peu de resultats sont disponibles pour les reactions de production de mesons vers l'arriere et leur interpretation est difficile. Le mecanisme d'echange de baryon est beaucoup plus complique que l'echange de meson. L'etude des reactions π-p → ΛavK0 et π-p → ΛavK*0890 avec des π- incidents de 8 Gev/c, basee sur le formalisme des poles de Regge et les amplitudes de diffusion dans le canal u, a montre que la polarisation du Λ est voisine de 1 et que ces reactions sont dominees par des echanges de trajectoires non naturelles; ce resultat peut aussi s'expliquer par la difference entre les couplages d'octet pour les trajectoires naturelles et non naturelles. La recherche de systeme mesonique exotique dans la reaction π+ + p → Λav + K++ a 12 GeV/c n'a pas permis de mettre en evidence l'existence d'un tel systeme mais des limites superieures sur leurs sections efficaces de production dont donnees; elles sont comparables a celles de la reaction π-p → Λav + K*890, en accord avec les predictions de la dualite a deux composantes

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Additional details

Additional titles

Original title (French)
Etude de la production de Λ dans les interactions π

Publishing Information

Imprint Pagination
198 p.
Report number
CEA-N--2123