2005/02/28 by R. Álvarez-Rodríguez, R. Alvarez-Rodriguez, E. Moya de Guerra +1 · 1 citation
Physics and Astronomy · #Atomic and Molecular Physics #Nuclear physics research studies #Quantum Chromodynamics and Particle Interactions #nucl-th
paper · pdf · doi:10.1103/physrevc.71.044308
published as Phys.Rev. C71 (2005) 044308 · 14 pages, 5 figures, to be published in Phys. Rev. C
arxiv created 2005/02/28 · openalex publication_date 2005/04/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study Fermi transitions and isospin mixing in an isotopic chain (^70\text\ensuremath-78Kr) considering various approximations that use the same Skyrme-Hartree-Fock single-particle basis. We study Coulomb effects as well as the effect of BCS and quasiparticle random phase approximation (QRPA) correlations. A measure of isospin mixing in the approximate ground state is defined by means of the expectation value of the isospin operator squared in N=Z nuclei (which is generalized to N\ensuremath≠Z nuclei). Starting from a strict Hartree-Fock approach without Coulomb interaction, it is shown that the isospin breaking is negligible, on the order of a few per thousand for (N\ensuremath-Z)=6, increasing to a few percent with Coulomb interaction. Pairing correlations induce rather large isospin mixing and Fermi transitions of the forbidden type (\ensuremathβ^\ensuremath- for N\ensuremath≤Z, and \ensuremathβ+ for N\ensuremath≥Z). The enhancement produced by BCS correlations is compensated to a large extent by QRPA correlations induced by isospin-conserving residual interactions that tend to restore isospin symmetry.