Ab initio description of monopole resonances in light- and medium-mass nuclei

Abstract

The paper is the third of a series dedicated to the ab initio description of monopole giant resonances in mid-mass closed- and open-shell nuclei via the so-called projected generator coordinate method. The present focus is on the computation of the moments $$m_k$$ m k of the monopole strength distribution, which are used to quantify its centroid energy and dispersion. First, the capacity to compute low-order moments via two different methods is developed and benchmarked for the $$m_1$$ m 1 moment. Second, the impact of the angular momentum projection on the centroid energy and dispersion of the monopole strength is analysed before comparing the results to those obtained from consistent quasi-particle random phase approximation calculations. Next, the so-called energy weighted sum rule (EWSR) is investigated. First, the appropriate ESWR in the center-of-mass frame is derived analytically. Second, the intrinsic EWSR is tested in order to quantify the (unwanted) local-gauge symmetry breaking of the presently employed chiral effective field theory ($$\chi $$ χ EFT) interactions. Finally, the infinite nuclear matter incompressibility associated with the employed $$\chi $$ χ EFT interactions is extracted by extrapolating the finite-nucleus incompressibility computed from the monopole centroid energy.