Resonances in scattering from potentials

In quantum mechanics, resonance cross section occurs in the context of quantum scattering theory, which deals with studying the scattering of quantum particles from potentials. The scattering problem deals with the calculation of flux distribution of scattered particles/waves as a function of the potential, and of the state (characterized by conservation of momentum/energy) of the incident particle.

Source: Wikipedia — Resonances in scattering from potentials (CC BY-SA 4.0)