Identification of low-energy isovector octupole states in ¹⁴⁴Nd

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 3_i ⁻→3₁ ^- transitions. For the transition from the "mixed-symmetry" octupole state to the symmetric 3₁ ⁻ state we expect a strong M1 component.