Soft gluons in logarithmic summations
Abstract
We demonstrate that all the known single and doublelogarithm summations for a parton distribution function can be unified in the Collins Soper resummation technique by applying soft approximations appropriate in different kinematic regions to real gluon emissions. Neglecting the gluon longitudinal momentum, we obtain the k_{T} (doublelogarithm) resummation for twoscale QCD processes, and the Balitsky Fadin Kuraev Lipatov (singlelogarithm) equation for onescale processes. Neglecting the transverse momentum, we obtain the threshold (doublelogarithm) resummation for twoscale processes, and the Dokshitzer Gribov Lipatov Altarelli Parisi (singlelogarithm) equation for onescale processes. If we keep the longitudinal and transverse momenta simultaneously, we derive a unified resummation for a large Bjorken variable x, and a unified evolution equation appropriate for both intermediate and small x.
 Publication:

European Physical Journal C
 Pub Date:
 September 1999
 DOI:
 10.1007/s100529900118
 arXiv:
 arXiv:hepph/9903267
 Bibcode:
 1999EPJC...10..319L
 Keywords:

 High Energy Physics  Phenomenology
 EPrint:
 14 pages in Latex, 1 figure in postscript file