hadronnucleus

Hadronnucleus refers to the interaction between a hadron and a nucleus, typically described as a hadron–nucleus collision or scattering. The projectile is a hadron (for example a proton, pion, or kaon) and the target is a nucleus with mass number A. The process can be elastic, with the internal structure of the nucleus remaining intact, or inelastic, featuring excitation or breakup and production of secondary particles.

Theoretical treatment often uses multiple-scattering formalisms. The Glauber model, based on the eikonal approximation, treats the nucleus as a collection of nucleons along the projectile’s path and sums over successive scatterings. Observables include the total, elastic, and inelastic cross sections, as well as differential cross sections that reveal angular and momentum-transfer distributions. At high energies, the projectile may interact with several nucleons, producing cascades of secondaries inside the nucleus (intranuclear cascade). Attenuation of the hadron beam and medium effects are central features of these descriptions.

Nuclear effects modify hadron production and propagation. Shadowing and anti-shadowing of parton distributions at small and moderate Bjorken x, the EMC effect at larger x, and final-state interactions within the nucleus influence outcomes. These effects are encoded in nuclear parton distribution functions and transport models, and are important for fixed-target experiments, cosmic-ray physics, and neutrino detectors.

Common projectiles include protons, pions, and kaons; targets range from light to heavy nuclei such as carbon, iron, and lead. Energies span from hundreds of MeV to TeV scales. Hadron–nucleus data constrain interaction models used in particle and astroparticle physics and in the interpretation of atmospheric air showers.