A new unintegrated gluon distribution to probe saturation physics in DIS
by
Zoom
CERN
Understanding the relation between QCD evolution in the Bjorken limit and the Regge limit is crucial to achieve a complete and smooth picture of proton and nuclear structure. The hope in the small x regime (where gluon density is expected to reach saturation and the naif partonic breaks down), was that by computing higher order corrections to small x evolution (BK equations) one would capture more and more of the physics at moderate x (DGLAP evolution). However, this research program has encountered some challenges. At NLO large collinear logarithms are present and need to be resummed spoiling the renormalization group structure established at LO.
In order to overcome these formal difficulties, we revisit the shock wave approach for high energy scattering. A new gauge invariant operator definition of the unintegrated gluon distribution that accounts systematically for the collinear limit of structure functions emerges naturally in our framework. I will discuss in particular inclusive DIS and DVCS as first applications
Based on 2001.06449 and 2006.14569 in collaboration with Renaud Boussarie.