5 research outputs found
Soft Gluons in Logarithmic Summations
We demonstrate that all the known single- and double-logarithm 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 (double-logarithm) resummation for two-scale QCD processes,
and the Balitsky-Fadin-Kuraev-Lipatov (single-logarithm) equation for one-scale
processes. Neglecting the transverse momentum, we obtain the threshold
(double-logarithm) resummation for two-scale processes, and the
Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (single-logarithm) equation for
one-scale processes. If keeping the longitudinal and transverse momenta
simultaneously, we derive a unified resummation for large Bjorken variable ,
and a unified evolution equation appropriate for both intermediate and small
.Comment: 14 pages in Latex, 1 figure in postscript fil