RESUMEN
Three ΔI=1 bands with the πg_{9/2}âνg_{9/2} configuration have been identified in _{35}^{74}Br_{39}. Angular distribution, linear polarization, and lifetime measurements were performed to determine the multipolarity, type, mixing ratio, and absolute transition probability of the transitions. By comparing these experimental observations with the corresponding fingerprints and the quantum particle rotor model calculations, the second and third lowest bands are, respectively, suggested as the chiral partner and one-phonon wobbling excitation built on the yrast band. The evidence indicates the first chiral wobbler in nuclei.
RESUMEN
Two pairs of positive-and negative-parity doublet bands together with eight strong electric dipole transitions linking their yrast positive- and negative-parity bands have been identified in ^{78}Br. They are interpreted as multiple chiral doublet bands with octupole correlations, which is supported by the microscopic multidimensionally-constrained covariant density functional theory and triaxial particle rotor model calculations. This observation reports the first example of chiral geometry in octupole soft nuclei.
RESUMEN
An assembly for a commercial Ga(+) liquid metal ion source in combination with an ion transportation and focusing system, a pulse high-voltage quadrupole deflector, and a beam diagnostics system has been constructed in the framework of the iThemba LABS (Cape Town, South Africa)-JINR (Dubna, Russia) collaboration. First, results on Ga(+) ion beam commissioning will be presented. Outlook of further experiments for measurements of charge breeding efficiency in the electron string ion source with the use of external injection of Ga(+) and Au(+) ion beams will be reported as well.
RESUMEN
Negative-parity bands in the vicinity of 156Gd and 160Yb have been suggested as candidates for the rotation of tetrahedral nuclei. We report the observation of the odd and even-spin members of the lowest energy negative-parity bands in 160Yb and 154Gd. The properties of these bands are similar to the proposed tetrahedral band of 156Gd and its even-spin partner. Band-mixing calculations are performed and absolute and relative quadrupole moments deduced for 160Yb and 154Gd. The values are inconsistent with zero, as required for tetrahedral shape, and the bands are interpreted as octupole vibrational bands. The failure to observe the in-band E2 transitions of the bands at low spins can be understood using the measured B(E1) and B(E2) values.
