Localized N, Λ, Σ, and Ξ single-particle potentials in finite nuclei calculated with SU6 quark-model baryon-baryon interactions

Localized single-particle potentials for all octet baryons, N, Lambda, Sigma, and Xi, in finite nuclei, C-12, O-16, Si-28, Ca-40, Fe-56, and Zr-90, are calculated using the quark-model baryon-baryon interactions. G matrices evaluated in symmetric nuclear matter in the lowest order Brueckner theory (LOBT) are applied to finite nuclei in local density approximation. Nonlocal potentials are localized by a zero-momentum Wigner transformation. Empirical single-particle properties of the nucleon and the Lambda hyperon in a nuclear medium have been known to be explained semiquantitatively in the LOBT framework. Attention is focused in the present consideration on predictions for the Sigma and Xi hyperons. The unified description for the octet baryon-baryon interactions by the SU6 quark model enables us to obtain less ambiguous extrapolation to the S=-1 and S=-2 sectors based on the knowledge in the NN sector than other potential models. The Sigma mean field is shown to be weakly attractive at the surface, but turns out to be repulsive inside, which is consistent with the experimental evidence. The Xi hyperon s.p. potential is also attractive at the nuclear surface region, and inside it fluctuates around zero. Hence Xi hypernuclear bound states are unlikely. We also evaluate energy shifts of the Sigma(-) and Xi(-) atomic levels in Si-28 and Fe-56, using the calculated s.p. potentials.