IDENTICAL BANDS AT NORMAL DEFORMATION - NECESSITY OF GOING BEYOND THEMEAN-FIELD APPROACH

The validity of BCS theory has been questioned because the appearance of normally deformed identical bands in odd and even nuclei seems to c ontradict the conventional understanding of the blocking effect. This problem is examined with the projected shell model (PSM), which projec ts good angular momentum states and includes many-body correlations in both deformation and pairing channels. Satisfactory reproduction of i dentical band data by the PSM suggests that it may be necessary to go beyond the mean field to obtain a quantitative account of identical ba nds.