SCALAR AND VECTOR-MESON PRODUCTION AND 2-STEP PROCESSES IN THE (K-,K-12() REACTION ON C)

The double strangeness exchange reaction (K-, Kf) is investigated with respect to the subthreshold production of scalar and vector mesons (f (0)/a(0)/phi) decaying into K+K- and the two-step processes induced by intermediate mesons and Xi- hyperons at p(K-)= 1.66 GeV/c using a sci ntillating fiber active target. The differential cross section (< d si gma/d Omega(L) >) averaged over the angular interval (2.3(0) less than or equal to theta(K+)(L) less than or equal to 14.7(0)) for the sub-t hreshold f(0)/a(0)/phi meson production with the K+K- decay is 11 +/- 6 mu b/sr at 0.6 less than or equal to p(K+) < 0.95 GeV/c. The present result differs significantly from the theoretical calculation which p redicts the contribution of the f(0)/a(0)/phi meson production to be p redominant in the (K-, K+) reaction below p(K+) = 0.95 GeV/c. We found a sizable contribution from two-step (K-, K+) processes, characterize d by production of two S = -1 hyperons, consistent with the result of the intra-nuclear cascade (INC) model calculation with respect to the meson-induced hyperon (or hyperon resonance) pair production in the mo mentum region 0.6 less than or equal to p(K+) < 0.95 GeV/c. The observ ed enhancement of the cross section for the two-step Lambda Lambda pro duction beyond the prediction of the INC model at p(K+) similar or equ al to 1.1 GeV/c could be due to the Xi(-) p --> Lambda Lambda reaction in C-12. (C) 1997 Published by Elsevier Science B.V.