Hyperon dynamics and production of multi-strangeness hypernuclei in heavy-ion collisions at 3A GeV

Abstract

Within a microscopic transport model, systematic investigation of hyperon production and hypernucleus formation up to strangeness S=−2 is carried out for 197Au + 197Au and 40Ca + 40Ca at the incident energy of 3A GeV. 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 Ξ hyperons and double Λ 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 ΛΛ4,5X are single-peak and more than two orders of magnitude lower than that of Λ3H. Formation of double Λ hypernuclei through Ξ hypernuclei as intermediate states is also discussed in terms of kinematics. Production of light double Λ hypernuclei, i.e., ΛΛ4,5H, ΛΛ4−7He, ΛΛ5Li is estimated to be at a level of μb in the case of 197Au + 197Au and two further orders of magnitude lower in that of 40Ca + 40Ca collisions.