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.

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A sample of K^3 events, detected in the CERN 1.1m'' heavy-liquid bubble chamber, has been used to investigate the^?^ dependence of the form factors, giving Ç(0) = 1.1 ± 1.0 and ï(6.6 m^) = 0.34 ± 0.20, for \+ = 0.027. A three parameter fit gives a value for X+ = 0.025 ± 0.017 in good agreement with the preceding Ke3 analysis.

A model independent détermination of the form factors %(q^) andhas been made, measuring, in intervais of , the partial branching ratio T(^^-^)lT{¥i%-^) and using the results of the Dalitz plot density analysis. No expéri mental évidence has been found for a strong déviation from a linear dependence of the form factors. Within this ap proximation a combined analysis of the Kgj and KjJ^j Dalitz plots gives the parameters ~ ~ 0.017 ± 0.011 or alter natively = 1.3 ± 0.7 and {(4.4 m\) = 0.45 ± 0.13, with in both cases a fitted value of \+ = 0.025 ± 0.007.