Ab initio computation of the 17F proton-halo state and resonances in A = 17 nuclei

We perform coupled-cluster calculations of the energies and lifetimes of single-particle states around the doubly magic nucleus 16O based on chiral nucleon-nucleon interactions at next-to-next- to-next-to-leading order. To incorporate effects from the scattering continuum, we solve the coupled- cluster equations with a Gamow-Hartree-Fock basis. Our calculations for the 1/2+ proton-halo state in 17F and the 1/2+ state in 17O agree well with experiment, while the calculated spin-orbit splitting between d5/2 and d3/2 states is too small due to the lack of three-nucleon forces. We find that continuum effects yield a significant amount of additional binding energy for the 1/2+ and 3/2+ states in 17O and 17F.