Effects of vibrational and pairing correlations on Isospin mixing in the higher Tamm-Dancoff approximation
Résumé
In the framework of the Higher Tamm-Danco Approximation which allows for a consis- tent treatment of pairing and quadrupole vibrational correlations preserving the particle- number symmetry and the Pauli principle, we compare the isospin content of ground and excited K = 0+ states including either type of the above mentioned correlations using an approximate projection-after-variation technique for isospin. The pairing correlations are described with a delta interaction using the same strength in the T = 0 and T = 1 channels, whereas the vibrational correlations are treated with an isoscalar quadrupole- quadrupole interaction. As a rst study, we apply this approach in the N = Z, even-even 16O nucleus. For the same amount of correlations measured by the diusivity of Fermi surface or depletion of particle-hole vacuum in the ground-state solution, we nd very similar isospin mixing in the ground state for both types of correlations, but dierent patterns for the distribution in the calculated solutions of the expectation value of the square of the isospin operator.