Three-dimensional angular momentum projection in relativistic mean-field theory

Based on a relativistic mean-field theory with an effective point coupling between the nucleons, three-dimensional angular momentum projection is implemented for the first time to project out states with designed angular momentum from deformed intrinsic states generated by triaxial quadrupole constraints. The same effective parameter set PC-F1 of the effective interaction is used for deriving the mean field and the collective Hamiltonian. Pairing correlations are taken into account by the BCS method using both monopole forces and zero-range \ensuremath{\delta} forces with strength parameters adjusted to experimental even-odd mass differences. The method is applied successfully to the isotopes $^{24}\mathrm{Mg}$, $^{30}\mathrm{Mg}$, and $^{32}\mathrm{Mg}$.