rescattering

Rescattering, in physics, refers to secondary scattering events in which particles produced by an initial interaction collide again with other particles or with the surrounding medium before exiting the system. It is a form of final-state interaction that can occur in nuclear, particle, and astrophysical contexts. In high-energy collisions, rescattering encompasses elastic and inelastic interactions of outgoing hadrons as they traverse nuclear matter or a dense hadronic medium.

In nuclear and particle physics, rescattering is particularly important in heavy-ion and neutrino experiments. In intranuclear cascades, produced mesons and baryons propagate through the residual nucleus and may scatter off nucleons, be absorbed, or undergo charge-exchange reactions. In neutrino-nucleus scattering, final-state interactions modify the observed final-state topologies and energy distributions, complicating the extraction of the primary interaction cross section and affecting event classification.

Modelling rescattering relies on transport or cascade approaches that simulate successive collisions and decays as particles move through matter. Examples include intranuclear cascade models, Boltzmann-Uehling-Uhlenbeck-type frameworks, and hadronic afterburners used in heavy-ion simulations. These models track cross sections, angular distributions, and energy loss for elastic, inelastic, and absorption processes, providing a means to connect the primary interaction with observed final states.

Experimental consequences include modified momentum spectra, altered particle yields, and distorted resonance signals. Rescattering can obscure or mimic signals of new physics, influence particle correlations, and affect reconstruction efficiencies. It also yields information about the properties of the nuclear medium, such as density, absorption lengths, and the strength of final-state interactions.