Energy Scale and Coherence Effects in small-x Equations

Abstract

I consider the next-to-leading,high-energy cluster expansion of large-k double-jet production in QCD, and I determine the corresponding one-loop quark and gluon impact factors, for a self-consistent energy scale. The result shows that coherent angular ordering of emitted gluons holds for hard emission also, and singles out a scale which is essentially the largest virtuality in the process. Both remarks are relevant for the precise deter- mination of the BFKL kernel at the next-to-leading level.