Interacting boson model of collective states I. The vibrational limit

Relation betweenE(5)models and the interacting boson model

“…This is so specially in the E(5), for which the χ 2 value reaches a minimum for N small (N ≈ 7) and from there on increases notably as a function of N . Globally, the best agreement is obtained for the E(5)-β 4 Hamiltonian and the worst for the E(5) case. For the case of very large number of bosons and Hamiltonians with O(5) symmetry we have confirmed the results of [29,30], i.e., the only E(5) model that can be reproduced exactly by the IBM is E(5)-β 4 , corresponding such a Hamiltonian with the critical point of the model (r 1 = 0).…”

O(6)-symmetry breaking in theγ-soft nucleusXe126and its evolution in the light stable xenon isotopes

“…The IBM-1 Hamiltonian posseses inherent U(6) symmetry which can be used as a powerful algebraic tool for classifying the nature of low-lying collective states of even-even nuclei into three symmetry classes: U(5) [3], SU(3) [4], and O(6) [5]. The presence of a symmetry is related to the conservation of certain quantum numbers.…”

Meaning ofS−Ddominance

“…The S and D bosons used in the IBA model [2,3] are different from the ones that appears in a quadrupolequadrupole+pairing (Nilsson like) calculation. Using our model hamiltonian we have shown that one cannot ignore the importance of the high angular momentum bosons in the description of the ground sate rotational band, even if the occupation probabilities of these bosons are very small.…”

“…The interacting boson approximation (IBA) [2,3,4] assumes that the elementary excitation used for the description of the low energy nuclear spectra in open shell nuclei are formed by pairs of nucleons coupled to angular momentum 0 and 2 (S and D). These excitations behave in this approximation as bosons.…”