Isospin and deformation studies in the odd-odd N=Z nucleus Co54

High-spin states in the odd-odd N=Z nucleus Co54 have been investigated by the fusion-evaporation reaction Si28(S32,1α1p1n)Co54. Gamma-ray information gathered with the Ge detector array Gammasphere was correlated with evaporated particles detected in the charged particle detector system Microball and a 1π neutron detector array. A significantly extended excitation scheme of Co54 is presented, which includes a candidate for the isospin T=1, 6⊃+ state of the 1f7/2-2 multiplet. The results are compared to large-scale shell-model calculations in the fp shell. Effective interactions with and without isospin-breaking terms have been used to probe isospin symmetry and isospin mixing. A quest for deformed high-spin rotational cascades proved negative. This feature is discussed by means of cranking calculations.