Jun 13 – 17, 2022
Berkeley, CA
US/Pacific timezone

Seniority symmetry breaking in semimagic 94Ru

Not scheduled
Berkeley, CA

Berkeley, CA

Lawrence Berkeley National Laboratory
Oral Poster Presentations Poster Session


Bo Cederwall (KTH Royal Institute of Technology)


Direct fast-timing lifetime measurements were carried out on low-lying states in the semimagic (N = 50) nucleus 94Ru. The experiment was carried out as the first in a series of “FAIR-0” experiments with the DESPEC experimental setup at the Facility for Antiproton and Ion Research (FAIR). Excited states in 94Ru were populated primarily via the β-delayed proton
emission of 95Pd nuclei, produced in the projectile fragmentation of a 850 MeV/nucleon 124Xe beam. impinging on a 4 g/cm2 9Be target. While the B(E2:2+ → 0+) follows the expected behavior for conserved seniority symmetry, the intermediate 4+ → 2+ transition in the seniority multiplet exhibits drastic enhancement of transition strength in comparison with pure seniority model predictions as well as standard shell model predictions in the fpg proton hole space. The anomalous behavior is ascribed to a subtle interference between the lowest seniority ν = 2 and ν = 4, Iπ = 4+ states due the effect of in-shell cross-diagonal interactions. In addition, the observed strong hindrance of the 6+ → 4+ transition is attributed to the same mechanism but with a destructive interference.

Primary author

Bo Cederwall (KTH Royal Institute of Technology)


Biswarup et al., Das (KTH Royal Institute of Technology)

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