Resolve the multipolarity of the 435.6-keV transition

Determine the multipolarity of the 435.6-keV γ-ray transition that depopulates the E_x = 2532 keV, T_1/2 = 150(5) ns isomeric state in ^197Au.

Background

The 435.6-keV γ ray feeds the E_x = 2097 keV, Iπ = (25/2+) level from the E_x = 2532 keV isomeric state. Although the level and transition were confirmed in the present data, the available measurements did not provide an unambiguous multipolarity assignment.

Resolving this multipolarity would improve the characterization of the decay scheme and the electromagnetic structure of the neighboring isomeric states in 197Au.

References

It was not possible to unambiguously ascertain the multipolarity of the 435.6-keV γ ray deexciting this state.

— Singular observation of shape and spin hindrance in metastable nuclear decay of $^{197}$Au  (2610.25915 - Tandel et al., 19 Oct 2026) in Section discussing the newly established metastable state