Isobaric multiplet mass equation within nuclear density functional theory

Abstract

We extend the nuclear Density Functional Theory (DFT) by including proton-neutron mixing and contact isospin-symmetry-breaking (ISB) terms up to next-to-leading order (NLO). Within this formalism, we perform systematic study of the nuclear mirror and triple displacement energies, or equivalently of the Isobaric Multiplet Mass Equation (IMME) coefficients. By comparing results with those obtained within the existing Green Function Monte Carlo (GFMC) calculations, we address the fundamental question of the physical origin of the ISB effects. This we achieve by analyzing separate contributions to IMME coefficients coming from the electromagnetic and nuclear ISB terms. We show that the ISB DFT and GFMC results agree reasonably well, and that they describe experimental data with a comparable quality. Since the separate electromagnetic and nuclear ISB contributions also agree, we conclude that the beyond-mean-field electromagnetic effects may not play a dominant role in describing the ISB effects in finite nuclei.

High-precision mass measurements and production of neutron-deficient isotopes using heavy-ion beams at IGISOL

“…Our result, −58 372(21) keV, indicated that it is somewhat (by 112(299) keV) more bound than the extrapolated literature value, −58 260(298) keV [39]. Since we measured many isospin projection T z = (N − Z )/2 = +1 nuclei, we decided to investigate what kind of mass predic- tions we obtain for the T z = −1 mirror partners by combining our precise mass measurements of T z = +1 nuclei with the state-of-the-art theoretical calculations for mirror displacement energies (MDE) [3,4]. Such a method was proved to provide accurate predictions for lower mass numbers, such as A = 52 [3].…”

“…Such a method was proved to provide accurate predictions for lower mass numbers, such as A = 52 [3]. The theoretical calculations presented in this work employ extended Skyrme energy density functional SV ISB T;NLO with proton-neutron-mixed densities and isospin-symmetrybreaking terms in next to leading order [4].…”

“…Being close to the Z = N line, the protons and neutrons are filling the same orbitals, mainly the high-spin 1g 9/2 orbital above the subshell closure at N = Z = 40. This opens an interesting approach to investigating proton-neutron pairing [1,2] as well as isospin symmetry [3,4] in nuclei. Recent theoretical calculations for mirror (MDE) or triplet displacement energies (TDE) using extended Skyrme energy density functionals with proton-neutron-mixed densities and isospin-symmetry-breaking terms have yielded good agreement with experimental data in the lower mass region [3,4].…”

“…This opens an interesting approach to investigating proton-neutron pairing [1,2] as well as isospin symmetry [3,4] in nuclei. Recent theoretical calculations for mirror (MDE) or triplet displacement energies (TDE) using extended Skyrme energy density functionals with proton-neutron-mixed densities and isospin-symmetry-breaking terms have yielded good agreement with experimental data in the lower mass region [3,4]. For example, with next-to-leading-order isospin-symmetrybreaking terms included, the root mean square deviation (RMSD) to experimental data for T = 1 MDEs is 180 keV and only around 65 keV for TDEs [4].…”

Effects of finite nucleon size, vacuum polarization, and electromagnetic spin-orbit interaction on nuclear binding energies and radii in spherical nuclei

“…Since the nuclear interaction is much stronger than the EM one, the former determines most properties of the atomic nuclei. Nevertheless, the EM interaction plays an important role when one focuses on nuclear properties related to the isospin symmetry breaking [1][2][3][4][5][6][7][8][9][10]. For more details, see reviews, e.g., Ref.…”