L. Coquard

Robust test of E(5) symmetry in 128Xe

Low-lying collectively excited states of 128 Xe were investigated by γ-ray spectroscopy following the 12 C( 128 Xe, 128 Xe*) 12 C projectile Coulomb excitation reaction. Nineteen absolute E2 transition strengths were obtained including the first measurement of the critical B(E2) decays from the second and third J π = 0 + states. These data are compared with the theoretical predictions of the critical point symmetry E(5) and allow us to conclude that 128 Xe is not an E(5) nucleus as previously suggested, leaving 130 Xe as the most likely candidate among the Xe isotopes.

The beauty of good data: Unveiling the traces of mixed symmetry

The one-quadrupole phonon excitation of mixed symmetry, the 2+1,ms state, is a fundamental building block of nuclear structure. This article gives a summary of our recent experimental research on this excitation mode in the A = 90 and A = 130 mass regions.

Robust test of E(5) symmetry in {sup 128}Xe.

Low-lying collectively excited states of 128 Xe were investigated by γ-ray spectroscopy following the 12 C( 128 Xe, 128 Xe*) 12 C projectile Coulomb excitation reaction. Nineteen absolute E2 transition strengths were obtained including the first measurement of the critical B(E2) decays from the second and third J π = 0 + states. These data are compared with the theoretical predictions of the critical point symmetry E(5) and allow us to conclude that 128 Xe is not an E(5) nucleus as previously suggested, leaving 130 Xe as the most likely candidate among the Xe isotopes.

Robust test of E(5) symmetry inXe128

Low-lying collectively excited states of 128 Xe were investigated by γ-ray spectroscopy following the 12 C( 128 Xe, 128 Xe*) 12 C projectile Coulomb excitation reaction. Nineteen absolute E2 transition strengths were obtained including the first measurement of the critical B(E2) decays from the second and third J π = 0 + states. These data are compared with the theoretical predictions of the critical point symmetry E(5) and allow us to conclude that 128 Xe is not an E(5) nucleus as previously suggested, leaving 130 Xe as the most likely candidate among the Xe isotopes.

Isovector quadrupole excitations in the valence shell of vibrational nuclei

Coulomb excitation experiments in inverse kinematics of stable ions impinging on a carbon target at energies of about 85% of the respective Coulomb barriers have been performed in the A∼130 region. Proton‐neutron mixed‐symmetry one‐quadrupole phonon state 21,ms+ has been identified in several nuclides from the large B(M1;21,ms+→21+) value as compared to typical M1 strengths between low‐energy 2+ states. As an example, we focuss on the evolution of the 21,ms+ state in the N = 80 isotonic chain. The local proton‐neutron quadrupole‐quadrupole interaction strength is determined from these data within a schematic two‐state mixing model.