The Parton Model and its Applications

TL;DR

This paper reviews the development of the parton model within quantum field theory, demonstrating its derivation, implications of crossing symmetry, and application to various high-energy scattering processes with observed scaling behaviors.

Contribution

It provides a canonical quantum field theory derivation of the parton model and explores its implications for deep inelastic scattering and hadron collision processes.

Findings

Parton model derived with a transverse momentum cutoff.

Structure functions exhibit scaling behavior consistent with Bjorken limit.

Massive lepton pair production shows scaling in high-energy hadron collisions.

Abstract

This is a review of the program we started in 1968 to understand and generalize Bjorken scaling and Feynman's parton model in a canonical quantum field theory. It is shown that the parton model proposed for deep inelastic electron scatterings can be derived if a transverse momentum cutoff is imposed on all particles in the theory so that the impulse approximation holds. The deep inelastic electron-positron annihilation into a nucleon plus anything else is related by the crossing symmetry of quantum field theory to the deep inelastic electron-nucleon scattering. We have investigated the implication of crossing symmetry and found that the structure functions satisfy a scaling behavior analogous to the Bjorken limit for deep inelastic electron scattering. We then find that massive lepton pair production in collisions of two high energy hadrons can be treated by the parton model with an interesting scaling behavior for the differential cross sections. This turns out to be the first example of a class of hard processes involving two initial hadrons.