New unified evolution equation
Abstract
We propose a new unified evolution equation for parton distribution functions appropriate for both large and small Bjorken variables $x$, which is an improved version of the CiafaloniCataniFioraniMarchesini equation. In this new equation the cancellation of soft divergences between virtual and real gluon emissions is explicit without introducing infrared cutoffs, nexttoleading contributions to the Sudakov resummation can be included systematically. It is shown that the new equation reduces to the DokshitzerGribovLipatovAltarelliParisi equation at large $x$, to the BalitskyFadinKuraevLipatov (BFKL) equation at small $x$, and to the modified BFKL equations with a dependence on momentum transfer $Q$ and with unitarity, if hard virtual gluon contributions and correction to strong rapidity ordering are retained, respectively.
 Publication:

arXiv eprints
 Pub Date:
 July 1998
 DOI:
 10.48550/arXiv.hepph/9807437
 arXiv:
 arXiv:hepph/9807437
 Bibcode:
 1998hep.ph....7437L
 Keywords:

 High Energy Physics  Phenomenology
 EPrint:
 revised version, 21 pages in Latex, 2 figures in postscript