Λ spin–orbit splitting in heavy hypernuclei as deduced from DWIA analyses of the image reaction Original Research Article

By taking nuclear core excitations into account, detailed structure calculations of 89 ΛY have been performed as a function of the Λ spin–orbit splitting. The obtained wave functions have been used to estimate the (π+,K+) reaction cross sections within the distorted-wave impulse approximation (DWIA). A theoretical explanation is given quantitatively for the first time of how to understand the doublet substructure of each major peak observed in medium-heavy hypernuclear production. A small Λ spin–orbit splitting of around δ(0fΛ)=0.2 MeV is deduced, a value consistent with the small ΛN two-body spin–orbit interactions deduced from γ-ray measurements in three light hypernuclei.