Number projected isovector neutron–proton pairing effect in odd-mass nuclei

A formalism which enables one to strictlyconserve the number of particles when taking into accountthe isovector pairing correlations is presented in the case ofodd-mass nuclei. With this aim, we had to first establish theexpression of the projector for such systems. Expressionsof the ground state and its energy have been exhibited. Themodel has been numerically tested in the framework of aschematic model.