Theoretical description of the HERA data on $F_2$ at low $Q^2$

Abstract.

It is shown that the CKMT model for the nucleon structure function $F_2$ gives a good description of the recent HERA data at low and moderate $Q^2$. A fit to the same data, obtained with a modified version of the model in which a logarithmic dependence on $Q^2$ has been included, is also presented. For moderate values of $Q^2$, in the current available range of x, the first parametrization leads to a better description of the data.