PROMPT PROTON DECAY OF A WELL-DEFORMED ROTATIONAL BAND IN CU-58

An excited well-deformed rotational band has been observed in the N = Z odd-odd nucleus Cu-58. The first excited state in this band decays v ia gamma emission to the spherical states associated with the first mi nimum in the potential, thus providing for its unambiguous assignment to Cu-58. I, contrast, its bandhead decays via emission of a prompt 2. 4(1) MeV proton to an excited state in the daughter nucleus Ni-57. Thi s is the first observation of proton decay from states associated with a deformed secondary minimum in the potential. Self-consistent Hartre e-Fock calculations reproduce well both the large collectivity of this band and the general trend of its moment of inertia.