Identification of $\mathit{T}=0\mathrm{}$ and $\mathit{T}=1\mathrm{}$ Bands in the $\mathit{N}=\mathit{Z}=37\mathrm{}$ Nucleus ${}^{74}$Rb

The $\gamma$ decay of excited states in the $N=Z$ odd-odd nucleus ${}^{74}\mathrm{Rb}$ has been observed for the first time. The reaction ${}^{40}\mathrm{Ca}{(}^{40}\mathrm{Ca},\alpha \mathrm{pn}{)}^{74}\mathrm{Rb}$ at 128 MeV beam energy was used. The ground state rotational band can be interpreted as being formed from the $T=1\mathrm{}$ isobaric analog states of ${}^{74}\mathrm{Kr}$ with pairing correlations based on $T=1\mathrm{}$, $M_T=0\mathrm{}$ neutron-proton pairs. At higher rotational frequency, a $T=0\mathrm{}$ rotational band becomes energetically favored over the $T=1\mathrm{}$ ground state band, in agreement with the predictions of cranked shell model calculations which explicitly include $T=0\mathrm{}$ and $T=1\mathrm{}$ pairs.