Multiple quadrupole “phonon” excitations in 130Ba

Experiments on multiphonon states with proton–neutron mixed symmetry in vibrational nuclei

“…However, most nuclei exhibit spectra that correspond to more or less broken symmetries and are frequently described best with IBM Hamiltonians outside of the dynamical symmetries [46]. The Q-phonon scheme [63][64][65][66] provides approximations to the wave functions that often help to semi-quantitatively understand the decay properties of boson states in regions other than those for analytically solvable cases.…”

“…The Q-phonon scheme is, therefore, a convenient tool for understanding the main structural mechanism in the formation of collectivity and it is a particularly useful formalism for the design of new experiments. The Q-phonon scheme was introduced by Otsuka et al [64] and was developed by the Cologne-Tokyo collaboration [63][64][65][66][67][68][69].…”

Triaxiality and the determination of the cubic shape parameterK3from five observables

“…This scheme was suggested by T. Otsuka [12], and was developed by a Köln-Tokyo collaboration, e.g. [13,14,15,16]. The Q-phonon scheme implies that the wave functions of low-lying states are exhausted by only a few multiple Q-phonon configurations, where a Q-phonon itself is an excitation by the quadrupole operator.…”

The triaxial rotation vibration model in the Xe_Ba region

“…Recently, the Ba and Xe region with mass numbers A≈120 to 130 has been studied experimentally [6,[9][10][11][12][13][14][15] and interpreted by several models: They compare different approaches of the Interacting Boson Approximation (IBA) in the U(5) and the O(6) limits (with different E2 operators) [7] and the axial Rotation Vibration Model (RVM) and the Asymmetric Rotor Model (ARM) [8]. They exclude the ARM [9,11] because it cannot describe a K=0 band built on γ vibrations [11] and because of the wrong staggering of the 2 + , 3 + , 4 + , 5 + , .…”