First evidence for smooth band termination in valence space in the mass 130 region : spectroscopy of $^{127}$La
Résumé
High spin states in 127La have been studied using the 32S(100Mo,p4n) reaction at a beam energy of 155 MeV. Gamma rays were detected using the EUROBALL III spectrometer. One of the side bands in 127La is observed to be populated to a spin of 832+. These data are compared with cranked Nilsson-Strutinski calculations which suggest that the structure is a smoothly terminating band, in valence space, based upon a π[(g7/2d5/2)5(h11/2)2]⊗ν[(g7/2d5/2)12(h11/2)6(d3/2s1/2)2] configuration, which can carry a maximum spin of 47.5ħ. This is the first identification of such a structure in this mass region. (APS)