Year: 2020
Type: article
Abstract: Magnetic dipole ($M1$) excitations constitute not only a fundamental mode of nucleonic transitions, but they are also relevant for nuclear astrophysics applications. We have established a theory framework for the description of $M1$ transitions based on the relativistic nuclear energy density functional. For this purpose, the relativistic quasiparticle random phase approximation (RQRPA) is established using density-dependent point coupling interaction DD-PC1, supplemented with the isovector-pseudovector interaction channel in order to study unnatural parity transitions. The introduced framework has been validated using the $M1$ sum rule for core-plus-two-nucleon systems, and employed in studies of the spin, orbital, isoscalar, and isovector $M1$ transition strengths that relate to the electromagnetic probe in magic nuclei $^{48}\mathrm{Ca}$ and $^{208}\mathrm{Pb}$ and open shell nuclei $^{42}\mathrm{Ca}$ and $^{50}\mathrm{Ti}$. In these systems, the isovector spin-flip $M1$ transition is dominant, mainly between one or two spin-orbit partner states. It is shown that pairing correlations have a significant impact on the centroid energy and major peak position of the $M1$ mode. The $M1$ excitations could provide an additional constraint to improve nuclear energy density functionals in the future studies.
Source: Physical Review C
Authors: G. Kružić, T. Oishi, D. Vale, N. Paar
Institutions: University of Zagreb, Ericsson (Croatia)
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3010227004