pT-Broadening and production processes versus dipole/quadrupole amplitudes at next-to-leading order

Abstract

Through the systematic inspection of graphs in the framework of lightcone perturbation theory, we demonstrate that an identity between the evolution of pT-broadening amplitudes with the energy and the evolution of forward scattering amplitudes of color dipoles off nuclei holds at next-to-leading order accuracy. In the general case, the relation is not a graph-by-graph correspondence, neither does it hold strictly speaking for definite values of the momenta: Instead, it relates classes of graphs of similar topologies, and in some cases, the matching requires an analytical continuation in the appropriate longitudinal momentum variable. We check that the same kind of relation is also true at next-to-leading order between amplitudes for the production of dijets and quadrupole forward amplitudes.