Speaker
Boris Ermolaev
(Ioffe Physico-Technical Institute)
Description
Standard Approach (SA) for description of $g_1$ is based on the
DGLAP evolution equations and the special fits for the initial parton
densities. SA accounts for the total resummation of logs of $Q2$ and
lacks the total resummation of leading $ln(1/x)$. In order to meet the
small -$x$ experimental data, SA includes phenomenological singular
factors in the fits. They mimic the resummation of ln(1/x) and lead to
the steep rise of g_1 at small x . When the resummation is accounted
for, the fits can be drastically simplified.
The further advantage of our approach lays in analysis of DIS at small
Q2. Indeed, DGLAP cannot be applied to the region of small Q2
presently studied by COMPASS collaboration. Contrary to it, our approach
works in this kinematics and predicts a very week x-dependence of g_1
at small Q2 even at very small values of x. Instead, experimental
investigation of the g_1 dependence on the invariant energy 2pq would
extremely interesting because it allows one to estimate the impact of the
gluon initial density.
Primary author
Boris Ermolaev
(Ioffe Physico-Technical Institute)
