Extraction of ΛΛ scattering length

We determine ΛΛ scattering parameters from a ΛΛ invariant mass spectrum that was obtained by 12C(K-, K+ΛΛ) reaction at the KEK Proton Synchrotron. In the framework of Watson's procedure, the obtained scattering length and effective range 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 (ESC00) models are out of two standard deviations from the determined scattering parameters.