Identification of low-energy isovector octupole states in 144Nd

Abstract

Recently, first candidates for low-lying isovector states in the octupole sector were suggested. The unambiguous identification of those states will contribute to the decomposition of the octupole-octupole residual interaction in an isoscalar and isovector part. This will help us understand the octupole degree of freedom. In 144Nd the 3− state at 2778 keV is a good candidate for such a “mixed-symmetry’' octupole state. In order to clarify the nature of this state, a 143Nd(n, γ)-experiment was conducted with the EXILL-setup. Following neutron capture the 3− states are populated and EXILL provides the opportunity to determine the multipole-mixing ratios of the 3i−→31- transitions. For the transition from the “mixed-symmetry” octupole state to the symmetric 31− state we expect a strong M1 component.