$O(a)$ Improvement of Nucleon Matrix Elements

Abstract

We report on preliminary results of a high statistics quenched lattice QCD calculation of nucleon matrix elements within the Symanzik improvement programme. Using the recently determined renormalisation constants from the Alpha Collaboration we present a fully non-pertubative calculation of the forward nucleon axial matrix element with $O(a)$ lattice artifacts completely removed. Runs are made at $\beta =6.0$ and $\beta =6.2$, in an attempt to check scaling and $O(a^2)$ effects. We shall also briefly describe results for $<x>$, the matrix element of a higher derivative operator.

Comments: 3 pages, Latex, 4 figures, epsf.sty and espcrc2.sty needed, Talk given at LATTICE97. Figure 4 corrected