hadronic

Hadronic is an adjective used in particle physics to describe matter, processes, and phenomena related to hadrons—the composite particles made of quarks bound by the strong interaction. Hadrons include baryons (such as protons and neutrons) composed of three quarks and mesons (such as pions and kaons) composed of a quark–antiquark pair. All hadrons are color-neutral due to confinement in quantum chromodynamics (QCD). The term is often contrasted with leptonic, which refers to leptons that do not participate in strong interactions.

Hadronic physics covers the production, interaction, and decay of hadrons. The strong force governs these processes and is described by QCD; however, at low energies the theory is nonperturbative, requiring methods such as lattice QCD or effective theories. Experimental study involves hadron-hadron scattering, hadron decays, and energetic jets arising from quarks and gluons that hadronize into a stream of hadrons. Observables include hadronic cross sections, resonance spectra, decay rates, and form factors. Hadronic calorimeters measure energy deposition from hadrons in detectors.

In astrophysics, hadronic matter refers to matter composed of hadrons, such as the neutrons in a neutron star. In high-energy heavy-ion collisions, a quark-gluon plasma can hadronize into hadrons as it cools. The term hadronic also appears in contexts such as hadronic decays of heavy-flavor hadrons and hadronic resonances, indicating processes governed by the strong interaction.