The geometric Schwinger Model on the Torus II

The geometric Schwinger Model (gSM) is the theory of a U(1)-gauge field in two dimensions coupled to a massless Dirac Kaehler field. It is equivalent to a Schwinger model with Dirac fields #PHI#_a"b(x) carrying iso-spin 1/2. We consider this model on the Euclidean space time of a torus. In Part I we discussed in detail the zero mode structure of this model. The main aim of this Part is the calculation of the correlation functions of currents and densities. Since it turned out that the gSM illustrates the generally interesting structure of anomalous chiral symmetry breaking in a very transparent manner, we present our results in the more familiar language of Dirac fields. In the introduction to the first part of our investigations we mentioned as motivation for the study of the gSM on the torus the possibility of a systematic lattice approximation of this model. In the meanwhile this project was realized to a large extend. Here we give the details of the discussion of the different quantities in the continuum to which we applied the lattice approximation. For these we formulate the 'geometric' description by differential forms of quantities which we consider interesting in this context. (orig.)Available from TIB Hannover: RA 2999(94-142) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Model independent QED corrections to the process ep #-># eX

We give an exhaustive presentation of the semi-analytical approach to the model independent leptonic QED corrections to deep inelastic neutral current lepton-nucleon scattering. These corrections include photonic bremsstrahlung from and vertex corrections to the lepton current of the order #OMICRON#(#alpha#) with soft photon exponentiation. A common treatment of these radiative corrections in several variables - leptonic, hadronic, mixed, Jaquet-Blondel variables - has been developed and double differential cross-sections are calculated. In all sets of variables we use some structure functions, which depend on the hadronic variables and which do not have to be defined in the quark parton model. The remaining numerical integrations are twofold (for leptonic variables) or onefold (for all other variables). For the case of hadronic variables, all phase space integrals have been performed analytically. Numerical results are presented for a large kinematical range, covering fixed target as well as collider experiments at HERA or LEP x LHC, with a special emphasis on HERA physics. (orig.)Available from TIB Hannover: RA 2999(94-115) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman