We show how the generalised (or skewed) parton distributions of the proton, H(x, xi; k_t^2, mu^2), unintegrated over the partonic transverse momenta, can be calculated from the known conventional parton distributions, q(x, mu^2) and g(x, mu^2), for small values of the skewedness parameter xi. We demonstrate the procedure by numerically evaluating the skewed unintegrated gluon. We also provide a simple approximate phenomenological form of the distribution, which may be used to make more rapid predictions of observables.
@article{arxiv.hep-ph/0107149,
title = {Unintegrated generalised parton distributions},
author = {A. D. Martin and M. G. Ryskin},
journal= {arXiv preprint arXiv:hep-ph/0107149},
year = {2014}
}