Superdeformation in Zn-68: Evidence for a new, neutron-rich island of superdeformation in A similar to 70 nuclei

A superdeformed rotational structure is reported in the stable nucleus Zn-6 8. It has a transition quadrupole moment (Q(t)) of 2.5(-0.4)(+0.7) e b (bet a(2) approximate to 0.4), as measured by the residual Doppler shift method. Theoretical calculations suggest that two different configurations are pos sible candidates for this band. One is built without h(11/2) neutrons, as s een in superdeformed bands in the A similar to 60 region, while the other i nvolves one h(11/2) neutron in analogy with superdeformed bands in the A si milar to 80 region. The second of these candidate configurations is preferr ed, thus establishing a new, neutron-rich (relative to the line of beta sta bility) region of superdeformation with Z similar to 30 and N similar to 38 .