High-Spin Intruder States in the fp-Shell Nuclei and Isoscalar Proton-Neutron Correlations

We perform a systematic theoretical analysis of fully-aligned, high-spin f{sub 7/2}{sup n} seniority isomers and d{sub 3/2}{sup -1}f{sub 7/2}{sup n+1} intruder states in the A{approx}44 nuclei from the lower-fp shell. The configuration-interaction calculations, based on the nuclear shell model, are performed in the full sdfp configuration space allowing 1p-1h cross-shell excitations. The density functional theory calculations are carried out within the self-consistent Hartree-Fock approach with the Skyrme energy functional that reproduces empirical Landau parameters. While there is a nice agreement between experimental and theoretical relative energies of fully-aligned states in N>Z nuclei, this is no longer the case for the N=Z systems. The remaining deviation from the data is attributed to the isoscalar proton-neutron correlations. It is also demonstrated that the Coulomb corrections at high spins noticeably depend on the choice of the energy density functional.