Finite-temperature quantum field theory and structure functions of the nucleon

The deep inelastic scattering of leptons off a proton in the statistical model is considered. The interior of the nucleon is viewed as a thermalized assembly of up and down quarks and gluons. This enables the incorporation of features which are absent in the parton model. These include the presence of identical quarks and gluons in initial and final states and of quantum statistical correlations which have a role to play in the propagation of particles when considering Feynman diagrams containing internal lines in next-to-leading-order calculations. These features are incorporated through the use of Fermi-Dirac and Bose-Einstein distributions for quarks and gluons, respectively. Stimulated emission factors for final-state gluons and Pauli-blocking factors for final-state quarks are incorporated. The propagation of particles through a many-body medium is taken into account by using thermal Feynman rules for propagators and vertices. The statistical model could also be seen as an attempt to describe the interior of the nucleon at a more fundamental level than that attained through the use of arbitrary parton distributions containing many parameters in the parton model. 79 refs., 46 figs., 8 tabs