The tensor part of the Skyrme energy density functional. I. Spherical nuclei

T. Lesinski (1) , M. Bender (2, 3) , K. Bennaceur (1, 2) , T. Duguet (4) , J. Meyer (1)

1 IPNL - Institut de Physique Nucléaire de Lyon
2 DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
3 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan
4 NSCL, MSU - National Superconducting Cyclotron Laboratory, Michigan State University

We perform a systematic study of the impact of the J^2 tensor term in the Skyrme energy functional on properties of spherical nuclei. In the Skyrme energy functional, the tensor terms originate both from zero-range central and tensor forces. We build a set of 36 parameterizations, which covers a wide range of the parameter space of the isoscalar and isovector tensor term coupling constants, with a fit protocol very similar to that of the successful SLy parameterizations. We analyze the impact of the tensor terms on a large variety of observables in spherical mean-field calculations, such as the spin-orbit splittings and single-particle spectra of doubly-magic nuclei, the evolution of spin-orbit splittings along chains of semi-magic nuclei, mass residuals of spherical nuclei, and known anomalies of charge radii. Our main conclusion is that the currently used central and spin-orbit parts of the Skyrme energy density functional are not flexible enough to allow for the presence of large tensor terms.

Mots clés: tensor force; spin-orbit force; Skyrme interaction; single-particle energies; binding energies; charge radii

Domaines: Physique Nucléaire Théorique [nucl-th]

T. Lesinski, M. Bender, K. Bennaceur, T. Duguet, J. Meyer. The tensor part of the Skyrme energy density functional. I. Spherical nuclei. 2007. ⟨hal-00140169v2⟩