SUM-RULE ANALYSIS OF THE RENORMALIZED QUASI-PARTICLE RANDOM-PHASE-APPROXIMATION

The renormalized quasiparticle random-phase approximation (RQRPA) is a nalyzed by the use of sum-rule techniques in realistic model calculati ons. It is found that the RQRPA does not satisfy the Gamow-Teller S- - S+ = 3(N - Z) sum rule and that the violation mostly comes from the S - part of it. The violation also seems to be mass-dependent increasing towards lighter masses. At the same time also the double Gamow-Teller sum rule is seen to be violated. Possible restoration of the sum rule is seen in the inclusion of the scattering terms in the definition of the RQRPA phonon operators.