Rotating Nuclei at Extreme Conditions: Cranked Relativistic Mean Field Description

CRMF theory [1,2] represents the extension of relativistic mean field (RMF) theory to the rotating frame and thus provides a natural framework for the description of rotating nuclei at high spin. Available experimental data on rotating nuclei at extreme conditions of large deformation (superdeformation) and fast rotation in different mass regions allow to test the theoretical models (in our case the CRMF theory) in physical situations where pairing correlations are expected to play no or only a minor role. This is an especially important point considering the fact that in the framework of CRMF theory a consistent theoretical description of pairing correlations including fluctuations by number projection is still in a stage of development. Thus a systematic study of SD bands within CRMF theory has been undertaken. Detailed investigations have been performed in the A ∼ 140− 150 [2–5] and in the A ∼ 60 [6–8] mass regions. Experimental observables as dynamic moments of inertia J , kinematic moments of inertia J (1) in the A ∼ 60 mass region, absolute (Q0) and relative (∆Q0) charge quadrupole moments, effective alignments ieff and the single-particle ordering in the SD minimum (derived from the analysis of effective alignments) have been confronted with results of CRMF calculations without pairing. It was shown that this theory provides in general good agreement with available experimental data. All these results give us strong confidence that CRMF theory can be a powerful tool both for the interpretation of experimental data and for the microscopic understanding of the behaviour of rotating nuclei at extreme conditions. Considerable disagreement with experiment has so far only been found in the case of the ’SD’ band in Er [9]. In the present article, we report on investigations on the structure of SD bands observed recently in Ho [10] with the aim to understand better the origin of the discrepancies found in the Er case.