No abstract

No abstract

No abstract

The form factors of the semi-leptonic decays K"*"->• Tr^e"*"!» and K"*"->•-n^ii^v have been investigated using a sample of events detected in the CERN 1.1 m^ heavy liquid bubble chamber. Analyses have been carried out using methods indépendant of any assumption of the q dependence of the form factors in addition to the usual linear parametrizations. Consistent results have been obtained from separate studies of both Dalitz plot density distributions and the branching ratio. A parametrized global analysis of both decay modes gives the values ï(0) =-1.3 ± 0.7 and Ç(4.4M^)=-0.45 ± 0.13, or \ =-0.017 ± 0.011 both for a fitted value of X+ = 0.025 ± 0.007. K^a-AV K^j-TrOeV KJJ-TTV»', K^j-Tr^e^.. I-* Chercheur agréé à l'IISN, Belgique. ** Erkend onderzoeker by het IIKW, België. w. * This is désirable in order to check the validity of the lineai expansions, especially as laige corrélations exist between the parameters. The depth of the chamber was later increased to 110 cm, increasing the visible volume by a factor of three. See e.g. Young [4]. * The upper limit éliminâtes the influence of bremsstrahlung 7-rays.

A study has been made of the production of hyperfragments by the interactions of 800-MeV/c K~ mesons in nuclear emulsion. The frequency of production, estimated to be 5.3±0.3%, is about the same as for Kr mesons at rest. The hyperfragments are emitted predominantly in the forward direction and the ratio of nonmesonic to mesonic decays has been found to be 11.5±0.6, much greater than for K~ mesons at rest. The proportion of hyperfragments of short range (range in emulsion < 5 JJ) is also much greater. These and other observations indicate that the hyperfragments are heavier than those produced by K~ mesons at rest. In at least 65±4% of cases they come from heavy emulsion nuclei, in contrast to the situation for K mesons at rest where most hyperfragments appear to originate in light emulsion nuclei. A model is proposed which can account for many of the features of the hyperfragment production process. and all interactions or decays thus found were noted. No further decay of a hyperfragment was found.