Evidence for isovector neutron-proton pairing from high-spin states in N = Z <sup>74</sup>Rb
O'Leary CD., Svensson CE., Frauendorf SG., Afanasjev AV., Appelbe DE., Austin RAE., Ball GC., Cameron JA., Clark RM., Cromaz M., Fallen P., Hodgson DF., Kelsall NS., Macchiavelli AO., Ragnarsson I., Sarantites D., Waddington JC., Wadsworth R.
High-spin states in the odd-odd N = Z nucleus 3774Rb37 were studied using the 40Ca(40Ca,αnp) reaction. A previously observed odd-spin T = 0 band has been extended to Iπ = (31+) and an even-spin T = 0 band has been observed for the first time to Iπ = (22+); both have a π(g9/2)⊗ν(g9/2) structure. A strongly coupled low-spin T = 0, K = 3 band has been interpreted as being based upon a π3/2 ⊗ ν3/2 configuration. Cranked relativistic Hartree-Bogoliubov calculations, which are corrected for the t = 1 np-pair field by restoring isospin symmetry, reproduce the observed spectrum. These new results provide evidence for the existence of an isovector pair field that contains a neutron-proton component with the proper strength for ensuring isospin conservation.