Interrelation between the isoscalar octupole phonon and the proton-neutron mixed-symmetry quadrupole phonon in near spherical nuclei

Abstract

The interrelation between the octupole phonon and the low-lying proton-neutron mixed-symmetry quadrupole phonon in near-spherical nuclei is investigated. The one-phonon states decay by collective E3 and E2 transitions to the ground state and by relatively strong E1 and M1 transitions to the isoscalar 2+ state. We apply the proton-neutron version of the Interacting Boson Model including quadrupole and octupole bosons (sdf-IBM-2). Two F-spin symmetric dynamical symmetry limits of the model, namely the vibrational and the γ-unstable ones, are considered. We derive analytical formulae for excitation energies as well as B(E1), B(M1), B(E2) and B(E3) values for a number of transitions between low-lying states.

25 pages, 3 figures, LaTeX, epsfig. Nucl. Phys. A (in press)

References in corpus (1)

• Transition Rates between Mixed Symmetry States: First Measurement in 94Mo

Cited by in corpus (9)

• Evolution of octupole deformation and collectivity in neutron-rich lanthanides
• The decay of quadrupole-octupole $1^{-}$ states in ${}^{40}$Ca and ${}^{140}$Ce
• Mixed-symmetry octupole and hexadecapole excitations in the N=52 isotones
• Q-phonon description of low lying 1^- two-phonon states in spherical nuclei
• Octupole correlations in collective excitations of neutron-rich $N\approx 56$ nuclei
• Extended M1 sum rule for excited symmetric and mixed-symmetry states in nuclei
• Direct demonstration of the two-phonon structure of the $J^{\pi }=1_{4742\mathrm{keV}}^{-}$ state of ${}^{88}$Sr
• On neutron number dependence of B(E1;0+ --> 1-) reduced transition probability
• Quadrupole and octupole states in ${}^{152}$Sm using the proton-neutron interacting boson model