**Perturbative QCD lattice calculations**

Our group has initiated a program to **calculate the hadronic structure functions on a lattice**. The numerical simulations to compute the
forward nucleon matrix elements are done on the parallel computer
**Quadrics**. In order to extract the physical content of these
computations one has to calculate the renormalization or Z-factors. This can be done non-perturbatively or perturbatively. The perturbative calculations are performed in Leipzig.

We have **calculated the Z-factors for the first, second and third moments of the quark operators**
occuring in the corresponding operator product expansion in one-loop approximation on a
hypercubic lattice based on the **Wilson action** in quenched form. To this aim we have developed
a symbolic code written in **Mathematica**. Taking the symbolic
Feynman rules for a specific operator as input it computes analytically its lattice and continuum
matrix elements between quark states.

In order to reduce the dependence of the results on the lattice spacing (a) so-called
**improved actions** have been proposed. We have recalculated the Z-factors for the local
scalar, pseudo scalar, vector, axial vector and tensor (h1) currents in the scheme
of the **Sheikholeslami-Wohlert action** accompanied with rotations of the quark fields.
The mass independent renormalization scheme has been exploited and the corresponding
improvement coefficients have been computed.
*recent published papers*

LOCAL BILINEAR OPERATORS ON THE LATTICE AND THEIR PERTURBATIVE RENORMALIZATION INCLUDING O(A) EFECTS

NONPERTURBATIVE IMPROVEMENT AND RENORMALIZATION OF LATTICE OPERATORS

O(A) IMPROVEMENT OF NUCLEON MATRIX ELEMENTS

THE LIGHT HADRON MASS SPECTRUM WITH NONPERTURBATIVELY O(A) IMPROVED WILSON FERMIONS

LATTICE COMPUTATION OF STRUCTURE FUNCTIONS

A PRELIMINARY LATTICE STUDY OF THE GLUE IN THE NUCLEON.

PERTURBATIVE RENORMALIZATION OF LATTICE BILINEAR QUARK OPERATORS

POLARIZED NUCLEON STRUCTURE FUNCTIONS FROM LATTICE
QCD.

A LATTICE EVALUATION OF THE DEEP INELASTIC STRUCTURE
FUNCTIONS OF THE NUCLEON.

TOWARDS A LATTICE CALCULATION OF THE NUCLEON
STRUCTURE FUNCTIONS.

This page is maintained by
Holger Perlt,
* 01-19-98 *