Production of double-Λ hypernuclei at ( K−, K+) reaction points and their pionic decays

Abstract

Starting with the ( K −, K +) reaction on nuclear targets of mass number 9–12 ( 9Be, 10B, 11B, 12C), the probabilities of producing double-Λ and single-Λ hyperfragments at the reaction points have been evaluated on the basis of the statistical model. First, the Ξ particle produced abundantly in the quasi-free region is shown to be well absorbed into the nucleus through the Ξ slowdown by knocking out a nucleon. Then the formation of a double-Λ compound nuclear system is assumed together with its subsequent breaking-up into various hyperfragments. The theoretical pion spectra are presented for the weak decays of the double-Λ and single-Λ hypernuclei produced efficiently in this scenario, which can be utilized for the identification of their hyperfragments production. It is proposed that the observation of ΛΛ 5H with the 9Be target is most feasible and promising.