“Stiff” deformed nuclei, configuration dependent pairing and the $\beta$β and $\gamma$γ degrees of freedom

First observation of γ -soft and triaxial bands in Zr isotopes

“…One of the questions vividly discussed in recent works concerns the presence of surface vibrations in nuclei. In addition to questioning the presence of K=0, β vibrations there are also doubts about the origin of K=2, γ vibrations in nuclei (see reviews by Garrett [36] and Sharpey-Schafer [37]). The observation in this work of two K π =2 + bands in 102 Zr with their band heads well within the pairing gap, one of which shows features of a triaxial structure and the other of a γ soft vibrator suggests that there is a room for γ vibrations, though as mentioned above, mixing between the two as well as with 2-q.p.…”

Pear-shaped atomic nuclei

“…An extreme example of such behaviour is that of 152 Dy, whose shape under certain conditions has a ratio of major ( z -axis) to minor ( x -, y -) axes of 2 : 1 [2]. Vibrational quadrupole excitations can also arise, for example, if the shape is displaced along the symmetry axis from its equilibrium position, although the evidence for such β -vibrations has been questioned recently; see [3,4]. More complicated quadrupole degrees of freedom can arise if the shape is no longer axially symmetric but convincing evidence for triaxial systems is restricted to very few cases [5].…”

Bohr Hamiltonian with Hulthén plus ring-shaped potential for triaxial nuclei with Deformation-Dependent Mass term

“…Discussion on nature of such bands can be found in the recent review article [61]. The energy spectrum is given by equation 30and depends on four parameters, namely: the screening parameter τ in the β potential, the ring-shape parameters c and s of the γ potential and the mass deformation parameter a.…”