  Due to color confinement, hadrons are inseparable when studying strong
interactions. The paper mainly studies the scattering in the background field,
especially the scattering of quarks in the hadronic background field. We
discovered that the coupling constant within the background field is made up of
the distribution function of background field. The finding provides a
foundational comprehension of coupling constants, which significantly
contributes to our understanding of running coupling constant and the
perturbative nature of theory.
