Speaker
Description
The combined inclusive DIS data from HERA are described
with DGLAP fits at NLO and NNLO, combined with a model
for twist 4 corrections originating from the GBW saturation
model. Besides the higher twist effects, modifications
are introduced at small x to the input functions for the
twist 2 parton distribution functions that are inspired by
findings of QCD at high parton densities. It is shown that
both inclusion of the higher twist effects and the input
modification of the DGLAP fit lead to significant improvement
of the fit quality below Q^2 = 5 GeV^2. With the best fit
employing the NNLO DGLAP evolution combined with higher twist
corrections, a good desription of DIS data is obtained down
to Q^2 = 1 GeV^2. The impact of higher twist corrections on
the parton desity functions is presented.
