Ground-state and pairing-vibrational bands with equal quadrupole collectivity in Xe 124

The nuclear structure of Xe124 has been investigated via measurements of the β+/EC decay of Cs124 with the 8πγ-ray spectrometer at the TRIUMF-ISAC facility. The data collected have enabled branching ratio measurements of weak, low-energy transitions from highly excited states, and the 2+→0+ in-band transitions have been observed. Combining these results with those from a previous Coulomb excitation study, B(E2;23+→02+)=78(13) W.u. and B(E2;24+→03+)=53(12) W.u. were determined. The 03+ state, in particular, is interpreted as the main fragment of the proton-pairing vibrational band identified in a previous Te122(He3,n)Xe124 measurement, and has quadrupole collectivity equal to, within uncertainty, that of the ground-state band.