Characterization of quasiparticle states at and beyond stability in ytterbium isotopes: Spectroscopy of

Excited states in 175Yb, 176Yb and 177Yb were populated via the bombardment of a 176Yb target with a 750 MeV 136Xe beam. Gamma-ray decays from these states were measured with the AFRODITE multi-detector spectrometer. The rotational band previously assigned to the ground state of 177Yb has been reassigned to the first-excited state of 175Yb. A new rotational band based on the ground state of 177Yb is presented, and the band based on the K π = 4- two-quasiparticle state in 176Yb has been identified. Also a candidate for the rotational band based on the K π = 8-, T 1/2 = 11.4(3) s two-quasiparticle state in 176Yb has been found. Comparisons of gK values derived from in-band branching ratios are consistent with the ν9/2+[624] assignment to the ground state of 177Yb, the ν2{9/2+[624] ⊗ 1/2-[510]} assignment to the K π = 4- state and with the ν2{9/2+[624] ⊗ 7/2-[514]} assignment to the K π = 8- metastable excited state in 176Yb