Speaker
Description
The concepts of triaxiality and -softness are introduced based on the collective liquid model. Pertaining signatures are the quadrupole shape invariants derived from the E2 matrix elements, the energy ratios and the staggering of the energies of the band . Microscopic Triaxial Projected Shell Model (TPSM) calculations have been carried out for nine nuclei with extended sets of E2 matrix elements from COULEX.
Good agreement with the TPSM energies and individual E2 matrix elements is found. Triaxiality and -softness are discussed based on the derived signatures. The classical wobbling mode of the triaxial rotor (TR) is defined and its appearance in the quantal TR states is visualized by means of the spin coherent state representation. The modification of wobbling by the presence of high-j quasiparticles is discussed in frame work of the particle+TR (PTR) model, which leads to the classification as transverse (TW) and longitudinal (LW) wobbling. The instability of TW with increasing angular momentum is discussed for 135 Pr.
The microscopic TPSM calculations are consistent with the PTR results both accounting for the experiment. The TPSM resolves the apparent inconsistency of the PTR, which assumes a rigid TR core while the even-even neighbors display -softness, as the consequence of the missing exchange terms between the TR core and the valence quasiparticles.
