Collective Modes in Fast Rotating Nuclei

We report on a microscopic study of the electromagnetic response in fast rotating nuclei undergoing backbending with special attention at the orbital M1 excitations known as scissors mode. We find that the overall strength of the orbital M1 transitions evolves with the rotational frequency in parallel with the nuclear moment of inertia and, eventually, gets enhanced by more than a factor four above the critical backbending region. The physical implications of this result are discussed.