abstract

The phenomenology to be tested in two-dimensional QCD is first reviewed and ’t Hooft’s light-like gauge formulation of two-dimensional QCD in the \(1/N_{\rm colour}\) expansion developed. Then, the model is applied to a number of hadronic reactions involving electromagnetic currents and also to some purely hadronic interactions.

abstract

Using parton models which scale asymptotically, we discuss the role of parton and target masses in the approach to scaling, the transverse momentum of partons, and the shape of the structure functions.

abstract

The possibility of understanding low energy hadron dynamics in terms of point-like medium-mass quarks is discussed. After introducing the basic assumptions of the model and cataloging some empirical knowledge of quark wave functions, the ideas of the model are applied to the study of several phenomena, including baryon magnetic moments, radiative meson decays, \(G_{\rm A}/G_{\rm V}\), the charge radii of the neutron and the \(K^0\), and \(K_{\rm l_3}\) decay.

abstract

Quark fragmentation into hadrons, esp. nucleons, is studied fitting empirical fragmentation functions to \(e^+e^-\) annihilation data. We find fragmentation functions deviating from counting rule predictions as well as from scaling due to the threshold in kaon and nucleon production. Using these fragmentation functions we study particle production ratios in \(e\)p and large \(p_{\perp }\) hadronic reactions. In both cases we find the ratios p/\(\pi ^+\) and \(\overline {\rm p}/\pi ^-\) to agree roughly in magnitude with the measured ratios. The model is however inconsistent with the \(p_{\perp }^{-12}\) behaviour of large \(p_{\perp }\) proton spectra.

abstract

The independent emission model for the production of particles is generalized so as to include the pion–nucleon interaction in a simplified form. In this new model excited states of hadronic matter play an important role. Assuming that a thermal equilibrium between these states is established it is then possible to calculate the multiplicity distributions of charged and neutral pions. For \(\pi \)p- and pp-reactions a comparison with experimental results is given.