Is the chiral phase transition in non-compact lattice QED driven by monopole condensation?

We investigate the recent conjecture that the chiral phase transition in non-compact lattice QED is driven by monopole condensation. The comparison of analytic and numerical results shows that we have a quantitative understanding of monopoles in both the quenched and dynamical cases. We can rule out monopole condensation. (orig.)Available from TIB Hannover: RA 2999(93-025) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

The present status of non-compact lattice QED

We give a 1993 update of non-compact lattice QED, in particular the chiral condensate, finite size effects and meson mass ratios. We compare descriptions of the phase transition. Our previous conclusions remain valid. (orig.)SIGLEAvailable from TIB Hannover: RA 2999(93-178) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Spectroscopy and renormalisation group flow of a lattice Nambu-Jona-Lasinio model

We investigate a lattice Nambu-Jona-Lasinio model both by the Monte Carlo method and Schwinger-Dyson equations. A comparison allows the discussion of finite size effects and the extrapolation to infinite volume. We pay special attention to the identification of particles and resonances. This enables us to discuss renormalisation group flows in the neighbourhood of the critical coupling where the chiral symmetry breaking phase transition takes place. In no region of the bare parameter space do we find renormalisability for the model. (orig.)SIGLEAvailable from TIB Hannover: RA 2999(93-195) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Perturbative renormalization of lattice bilinear quark operators

Our aim is to compute the lower moments of the unpolarized and polarized deep-inelastic structure functions of the nucleon on the lattice. The theoretical basis of the calculation is the operator product expansion. To construct operators with the appropriate continuum behavior out of the bare lattice operators one must absorb the effects of momentum scales far greater than any physical scale into a renormalization of the operators. In this work we compute the renormalization constants of all bilinear quark operators of leading twist and spin up to four. The calculation is done for Wilson fermions and in the quenched approximation where dynamical quark loops are neglected. (orig.)21 refs.Available from TIB Hannover: RA 2999(96-034) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Lattice operators for moments of the structure functions and their transformation under the hypercubic group

For lattice operators that are relevant to the calculation of moments of nucleon structure functions we investigate the transformation properties under the hypercubic group. We give explicit bases of irreducible subspaces for tensors of rank #<=#4. (orig.)7 refs.Available from TIB Hannover: RA 299(96-031) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Recent results on the nucleon structure functions from lattice QCD

We report on recent results of a high statistics lattice calculation of the unpolarized and polarized structure functions of the nucleon. (orig.)9 refs.Available from TIB Hannover: RA 2999(95-203) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Towards a lattice calculation of the nucleon structure functions

We have initiated a programme to compute the lower moments of the unpolarised and polarised deep inelastic structure functions of the nucleon in the quenched approxiation. We review our progress to date. (orig.)SIGLEAvailable from TIB Hannover: RA 2999(94-227) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Seeking the equation of state of non-compact lattice QED

We perform a high statistics calculation of the equation of state for non-compact QED on large lattices. The calculation extends to fermionic correlation lengths of #approx#8, and it is combined with a finite size scaling analysis of the lattice data. (orig.)23 refs.Available from TIB Hannover: RA 2999(96-084) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

A lattice evaluation of the deep-inelastic structure functions of the nucleon

The lower moments of the unpolarized and polarized deep-inelastic structure functions of the nucleon are calculated on the lattice. The calculation is done with Wilson fermions and for three values of the hopping parameter #kappa#, so that we can perform the extrapolation of the chiral limit. Particular emphasis is put on the renormalization of lattice operators. The renormalization constants, which lead us from lattice to continuum operators, are computed perturbatively to one loop order as well as non-perturbatively. (orig.)14 refs.SIGLEAvailable from TIB Hannover: RA 2999(95-178) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

First results with non-perturbative fermion improvement

We present initial results for light hadron masses and nucelon structure functions using a recent proposal for eliminating all O(#alpha#) effects from Wilson fermion simulations in the quenched approximation. With initially limited statistics, we find a much more linear APE plot and a value of the axial coupling g_A nearer to the experimental point than with comparable runs using unimproved Wilson fermions. (orig.)8 refs.Available from TIB Hannover: RA 2999(96-142) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman