Use of the group velocity concept in acoustical resonances studies

The authors first review the fundamental notions involved in the group velocity concept. Then, they discuss how this concept may be usefully applied to the study of Regge trajectories. In acoustical scattering, the group velocity is related very simply to the frequency spacing between two consecutive resonances of the same wave. The group velocity appears also in the determination of resonance's widths and consequently of acoustic radiation. Finally, they discuss briefly the relationships between resonances, Regge trajectories, and group velocity in nuclear physics and elementary particles physics [J. Phys. France 50, 1943–1952 (1989)].