Determination of Leading Twist Non-Singlet Operator Matrix Elements by   QCD Sum Rules
  We use QCD sum rules to determine the twist-two non-singlet operator matrix elements and fixed x structure functions paying particular regard to the estimate of the errors. Particularly for the matrix element determination, we find large uncertainties due to radiative and higher dimension contributions. We consider the origin of these large corrections and comment on their consequences for other operator matrix element determinations. 
G.G.Ross (1), N.Chamoun (1) ((1) University of Oxford)