We critically examine, in selected 1p-shell nuclei, the theoretical procedure of determining nuclear transition matrix elements, by fits to low-energy electromagnetic and weak observables. We systematically study various fitting strategies using the latest database, and obtain a set of optimal one-body matrix elements. The onset of inadequacies of these sets in describing a given nuclear electroweak observable usually signals the breakdown of the 1p-shell model and/or importance of the two-body corrections. We compare the particle-hole conjugate nuclei ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ and ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$, and obtain effective amplitudes. We also study the mass-12 case and find a set of effective one-body amplitudes. The difference in the ${\mathit{p}}_{1/2}$ and ${\mathit{p}}_{3/2}$ radial wave functions plays an important role in our fits.

• Received 26 August 1994

DOI:https://doi.org/10.1103/PhysRevC.52.1947