Deep Inelastic Structure Functions: Decisive Tests of QCD

Abstract

The purpose of this talk is to discuss the present status of scaling violations in deep inelastic lepton-nucleon scattering processes. Specifically, I will discuss in great detail which experimentally measured structure functions (or moments thereof) have to be used in order to discriminate between various field theories of the strong interactions such as (non-abelian) QCD, abelian vector-gluon (\(\bar \psi\)ɤrΨAr), non-abelian scalar-gluon (\(\bar \psi\)λaΨϕa) , and abelian scalar-gluon (\(\bar \psi\)Ψϕ) theories. Moreover I will delineate the sensitivity of certain structure functions to the fundamental couplings of the theory, i.e., to the quark-gluon coupling and/or to the gluon self-couplings (triple gluon vertex) - a measurement of the latter would provide us with a direct and unambiguous test of the Yang-Mills structure of QCD which is so very essential for asymptotic freedom. Furthermore, we will consider three-jet events with special emphasis on deep inelastic heavy quark (c,b,…) production via virtual Bethe-Heitler processes. Finally, I shall briefly discuss the relevance of non-leading 2-loop contributions to anomalous dimensions and the effetcs of “finite terms” in Wilson coefficients and their importance for the analysis of deep inelastic reactions such as the determination of moments of “sea” distributions from measured neutrino cross sections.