Journal of Theoretical and Applied Physics (JTAP) Number projected isovector neutron–proton pairing effect in odd-mass nuclei Volume 8 (2014) Issue 2, May and June 2014 2023 11 17 Number projected isovector neutron–proton pairing effect in odd-mass nuclei 10.1007/s40094-014-0118-8 EN Journal Article 2023 11 17 AbstractA formalism which enables one to strictly conserve the number of particles when taking into account the isovector pairing correlations is presented in the case of odd-mass nuclei. With this aim, we had to first establish the expression of the projector for such systems. Expressions of the ground state and its energy have been exhibited. The model has been numerically tested in the framework of a schematic model.