Phys.Rev. C 107, 044314 (2023)

A.D.Ayangeakaa, R.V.F.Janssens, S.Zhu, J.M.Allmond, B.A.Brown, C.Y.Wu, M.Albers, K.Auranen, B.Bucher, M.P.Carpenter, P.Chowdhury, D.Cline, H.L.Crawford, P.Fallon, A.M.Forney, A.Gade, D.J.Hartley, A.B.Hayes, J.Henderson, F.G.Kondev, Krishichayan, T.Lauritsen, J.Li, D.Little, A.O.Macchiavelli, D.Rhodes, D.Seweryniak, S.M.Stolze, W.B.Walters, J.Wu

Triaxiality and the nature of low-energy excitations in ⁷⁶Ge

NUCLEAR REACTIONS ²⁰⁸Pb(⁷⁶Ge, ⁷⁶Ge'), E=291, 304, 317 MeV; measured Eγ, Iγ, (⁷⁶Ge)γ-coin using the GRETINA array with 28 Ge crystals in one experiment at 304-MeV beam energy, and 42 Ge crystals in a second experiment at 291- and 317-MeV beam energies, both in coincidence with scattered particles detected by using the CHICO2 array of position-sensitive parallel plate avalanche counters at the ATLAS-ANL facility. ⁷⁶Ge; deduced levels, Jπ, γ-ray and Coulomb excitation yields analyzed by using the semiclassical, coupled-channel, Coulomb excitation least-squares code GOSIA, constrained by certain previouly known experimental nuclear structure parameters, E2, M1, E1 and E3 matrix elements, B(E2), B(M1), B(E1) and B(E3), spectroscopic quadrupole moments for five excited states, and evidence for rigid triaxial deformation at low excitation energies in ⁷⁶Ge, and magnitudes of the quadrupole invariants Q⁺², and expectation values of the quadrupole asymmetry parameters cos(3γ) for the members of the ground-state and the γ bands. Comparison with configuration interaction shell-model calculations and generalized triaxial rotor model, and with previous experimental data.

doi: 10.1103/PhysRevC.107.044314