Hadronizimi

Hadronizimi, known in English as hadronization, is the process by which quarks and gluons produced in high-energy interactions become colorless hadrons—mesons and baryons. It is a non-perturbative transition that occurs as partons reach a low energy scale where color confinement prevents the existence of free quarks or gluons.

After an initial parton shower described by perturbative QCD, the colored partons must combine into colorless states. Hadronization is modeled rather than derived from first principles because the relevant dynamics occur at low energy where the strong coupling is large.

Two broad classes of hadronization mechanisms are commonly used: fragmentation (where a high-energy parton develops a parton shower and the color string breaks to form hadrons) and recombination or coalescence (where nearby quarks combine into hadrons, especially in the hot, dense medium created in heavy-ion collisions). Fragmentation is implemented in string-inspired models (for example the Lund model) and cluster models; recombination is prominent in relativistic heavy-ion physics.

Hadronization affects observable quantities such as jet fragmentation functions, hadron momentum spectra, and baryon-to-meson ratios. Experimental data from electron–positron annihilation, deep inelastic scattering, and hadron colliders, as well as heavy-ion collisions, are used to tune hadronization models. Lattice QCD informs hadron properties but does not directly predict the hadronization process.

Understanding hadronizimi is essential for connecting parton-level calculations to measured hadron distributions and for interpreting collider and cosmic-ray data.