摘要

Within a microscopic transport model, systematic investigation of hyperon production and hypernucleus formation up to strangeness S=-2is carried out for Au-197 + Au-197 and Ca-40 + Ca-40 at the incident energy of 3AGeV. The spatial, temporal and density distributions of hyperon production, absorption and chemical freeze-out are investigated from novel perspectives. The rapidity and kinetic energy spectra of Xi hyperons and double hypernuclei are analyzed. It is revealed that the chemical balance of hyperon production is established in baryon-baryon channels while the opposite result is found in baryon-meson channels. It turns out that the rapidity spectra of X-4,5(Lambda Lambda) are single-peak and more than two orders of magnitude lower than that of (3)(Lambda) H. Formation of double Lambda hypernuclei through Xi hypernuclei as intermediate states is also discussed in terms of kinematics. Production of light double Lambda hypernuclei, i.e., (4,5)(Lambda Lambda) H, He-4-7(Lambda Lambda), (5)(Lambda Lambda) Li is estimated to be at a level of mu b in the case of 197Au + 197Au and two further orders of magnitude lower in that of Ca-40 + Ca-40 collisions.

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