Tilted Rotation and Backbending in an Odd-Proton Nucleus

Tilted-axis rotation, arising from Fermi-aligned configurations, has been observed for the first time to cause backbending in an odd-proton nucleus. In ${}^{181}\mathrm{Re}$, two $t$-bands are found to be energetically favored relative to the usual rotation-aligned $s$-bands, presenting an alternative form of cold nuclear rotation. Interactions between the bands are weak, and unambiguous comparisons with tilted-axis-cranking calculations can be made.