partonquarks

Partonquarks are a theoretical concept in particle physics, primarily used to describe the internal structure of hadrons such as protons and neutrons. The term "parton" was introduced by Richard Feynman in the late 1960s to explain experimental results from deep inelastic scattering experiments. These experiments showed that electrons scattering off protons seemed to be interacting with point-like constituents within the proton, rather than the proton as a whole. Feynman proposed that these constituents were partons.

Later, with the development of quantum chromodynamics (QCD), the theory of the strong nuclear force, it became understood that these partons are quarks and gluons. Quarks are fundamental particles that carry fractional electric charge and color charge. Gluons are the force carriers of the strong interaction, binding quarks together. A proton, for instance, is composed of three valence quarks (two up quarks and one down quark) and a dynamic sea of virtual quark-antiquark pairs and gluons.

The concept of partons is useful because at very high energies or short distances, the quarks and gluons inside a hadron behave almost as if they are free. This is known as asymptotic freedom. However, at lower energies or larger distances, the strong force becomes much stronger, confining the quarks and gluons within the hadron. Parton distribution functions (PDFs) are used in theoretical calculations to describe the probability of finding a parton with a certain fraction of the hadron's momentum. These functions are not derived from first principles but are determined experimentally. The term "partonquark" itself is not a standard or widely used term in physics literature; the constituents are simply referred to as partons, which are understood to be quarks and gluons.