Coherent proton–neutron contribution to octupole correlations in the neutron-deficient 114Xe nucleus

Gamma ray linear polarization and picosecond lifetimes have been measured for levels in the neutron deficient nucleus 114Xe using the EUROBALL IV spectrometer and the Cologne plunger device. The EUCLIDES Si-ball was used to improve the reaction channel selectivity. The linear polarization results have, for the first time, unambiguously determined the electromagnetic character of the dipole transitions de-exciting the negative parity level sequence, providing clear evidence for enhanced octupole collectivity. The discovery of two E3 transitions and the measurement of the lifetimes of the states depopulated by these transitions have allowed a quantitative determination of the octupole collectivity in the A≈112 mass region. The large measured B(E3) values, close to ≈70 W.u., are among the strongest observed hitherto and indicate a coherent proton–neutron contribution to the octupole moment.