Ab InitioShell Model Calculations with Three-Body Effective Interactions forp-Shell Nuclei

We present a qualitative improvement of the ab initio no-core shell model (NCSM) approach by implementing three-body interaction capability for $p$-shell nuclei. We report the first calculations using three-body effective interactions derived from realistic nucleon-nucleon potentials for ${}^{6}\mathrm{Li}$, ${}^{8}\mathrm{Be}$, and ${}^{10}\mathrm{B}$ and demonstrate that the use of three-body effective interactions speeds up the convergence of the NCSM approach. For ${}^{10}\mathrm{B}$, we predict ${J}^{\ensuremath{\pi}}{T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1}^{+}0$ ground state, contrary to the experimental observation of ${3}^{+}0$, when the $\mathrm{AV}{8}^{\ensuremath{'}}$ potential is used, indicating the need for true three-body forces.