Magnetic-dipole excitations as reference for the spin-orbit interaction in nuclei

Tomohiro Oishi, Goran Kruzic, Nils Paar

Published 2019-12-23Version 1

Magnetic dipole (M1) excitation is the leading mode of multi-fermion excitations by the magnetic field. This mode is closely connected with the spin-orbit (LS) interaction, that is of general relevance in atomic, molecular and nuclear physics, condensed matter physics and in many applications. We study possible relation between the nuclear M1 response and the energy splitting by the LS interaction, by employing the framework of relativistic nuclear energy density functional (RNEDF) that naturally describes the spin-orbit interaction due to the Dirac-Lorentz structure of the formalism. The relativistic Hartree-Bogoliubov model (RHB) is used to determine the nuclear ground state and single (quasi)particle energies, while the relativistic quasiparticle random phase approximation is established for the description of M1 excitation properties. It is shown that M1 excitations in the RNEDF framework provide a suitable tool to constrain the spin-orbit interaction, i.e., the splittings of the states that govern the M1 transition under consideration.