Isovector pairing and particle-number fluctuation effects on the spectroscopic factors of one-proton stripping and one-neutron pick-up reactions in proton-rich nuclei

Abstract

Expressions of the spectroscopic factors (SFs) corresponding to one-particle transfer reactions have been established using a schematic definition. These expressions have been derived by taking into account the isovector neutron-proton (np) pairing correlations and a particle-number projection in the framework of the generalized Sharp-BCS (SBCS) method. Recently proposed expressions of the projected wave-functions of odd-mass nuclei have been used for this purpose. The formalism has first been tested using the single-particle energies of the schematic picket-fence model. It is shown that the np pairing and particle-number fluctuation effects are far from negligible and they depend on the pairing gap parameter values. Their behavior is not the same when the parent nuclei are even-even or odd. Predictions dealing with the SFs corresponding to one-proton stripping and one-neutron pick-up reactions in proton-rich nuclei have then been established within the framework of the realistic Woods-Saxon model. It is shown that the np pairing effect as well as the particle-number projection effect are important and thus have to be included in future calculations of the SF corresponding to these kinds of reactions.