Superdeformed Bands and α-Cluster States in A~40 Nuclei

T. Sakuda and S. Ohkubo Department of Physics, University of Miyazaki, Miyazaki 889-2192, Japan a Department of Applied Science and Environment, University of Kochi, Kochi 780-8515, Japan b Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka 567-0047, Japan sakuda@cc.miyazaki-u.ac.jp The investigation of superdeformed (SD) rotational bands in Ar−Cr nuclei has received considerable attention. The collective aspects of these SD bands are particularly interesting subjects for nuclear structure studies. We have performed the α−cluster model calculations for the nuclei in this region and have shown that the observed energy spectra and E2 transitions are reproduced with good coincidence [1]. Figure 1 shows the experimental candidates for the α-cluster bands. The dotted and dashed lines connect the band heads of α-nh and 2α-mh cluster bands, respectively. The SD bands are also indicated by label SD. Our purpose is to clarify the relationship between the SD bands and 2α-cluster structure. The nucleus V provides the first link in the chain of 2α-mh cluster states in A=44−48 nuclei. Figure 2 shows the experimental positive-parity SD band of V [2], which shows fine collectivity. The investigation of the V using the 2α+K OCM is in progress and will be reported. [1] T. Sakuda and S. Ohkubo, Phys. Rev. C49, 149(1994); C51, 586(1995); C57, 1184(1998); Prog.Theor. Phys. Suppl. No.132, 103(1998); Phys. At. Nucl. 65, 703(2002); Nucl. Phys. A712, 59(2002); Nucl. Phys. A744, 77(2004). [2] F. Brandolini et al., Nucl. Phys. A693, 517(2001).