EXTRACTION OF Lambda Lambda SCATTERING LENGTH

We determine Lambda Lambda scattering parameters from a Lambda Lambda invariant mass spectrum that was obtained by C-12(K-, K+Lambda Lambda) reaction at the KEK Proton Synchrotron. In the framework of Watson's procedure, the obtained scattering length a(Lambda Lambda)=-0.10(-2.37)(+0.45) +/- 0.04 and effective range r(Lambda Lambda) =13.90(<-13.90)(+16.10) +/- 9.48 fm are most consistent with the values predicted by using the Nijmegen soft core models (NSC97's). However, the predicted values by using the Nijmegen hard-core ND (G-matrix) and the extended soft-core (ESCOO) models are out of two standard deviations from the determined scattering parameters.