Isospin mixing in a particle-number conserving microscopic approach

L. Bonneau (1) , J. Bartel (2) , P. Quentin (1, 3)

1 Theoretical Division [LANL]
2 DRS-IPHC - Département Recherches Subatomiques
3 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan

We calculate the isospin-mixing parameter for several Tz=-1, Tz=0 and Tz=1 nuclei from Mg to Sn in the particle-number conserving Higher Tamm-Dancoff approach taking into account the pairing correlations. In particular we investigate the role of the Coulomb interaction and the |Tz|=1 pairing correlations. To do so the HTDA approach is implemented with the SIII Skyrme effective nucleon-nucleon interaction in the mean-field channel and a delta interaction in the pairing channel. We conclude from this investigation that the pairing correlations bring a large contribution to isospin-symmetry breaking, whereas the Coulomb interaction turns out to play a less important role. Moreover we find that the isospin-mixing parameters for Tz=-1 and Tz=1 nuclei are comparable while they are about twice as large for Tz=0 nuclei (between 3% and 6%, including doubly magic nuclei).

Domaines: Physique Nucléaire Théorique [nucl-th]

L. Bonneau, J. Bartel, P. Quentin. Isospin mixing in a particle-number conserving microscopic approach. 2007. ⟨in2p3-00152347⟩