Low-lying level structure of $\Lambda$ hypernuclei and spin dependence of $\Lambda N$ interaction with antisymmetrized molecular dynamics

Abstract

$\Lambda N$ spin-spin and spin-orbit splittings in low-lying excitation spectra are investigated for $p$-shell $\Lambda$ hypernuclei on the basis of the microscopic structure calculation within the antisymmetrized molecular dynamics, where the $\Lambda N$ $G$-matrix interaction derived from the baryon-baryon interaction model ESC (extended soft core) is used. It is found that the ground-state spin-parity is systematically reproduced in the $p$-shell $\Lambda$ hypernuclei by tuning the $\Lambda N$ spin-spin and spin-orbit interactions so as to reproduce the experimental data of $^{4}_\Lambda$H, $^{7}_\Lambda$Li and $^9_\Lambda$Be. Furthermore, we also focus on the excitation energies of the excited doublets as well as the energy shifts of them by the addition of a $\Lambda$ particle.