QCD corrections to $F_L(x,Q^2)$

Abstract

We perform a numerical study of the QCD corrections to the structure function $F_L(x,Q^2)$ in the HERA energy range. The $K$--factors are of $O(30%)$ and larger in parts of the kinematic range. The relative corrections to $F_L^{c\overline{c}}$ turn out to be scale dependent and partially compensate contributions to the massless terms.