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