2010/10/09 by Eric Laenen, Lorenzo Magnea, Gerben Stavenga +1 · 1 citation
Physics and Astronomy · #hep-ph
paper · pdf · doi:10.1007/jhep01(2011)141
published as JHEP 1101:141,2011 · 66 pages, 19 figures
arxiv created 2010/10/09 · arxiv updated 2015/03/17
We consider the problem of soft gluon resummation for gauge theory amplitudes and cross sections, at next-to-eikonal order, using a Feynman diagram approach. At the amplitude level, we prove exponentiation for the set of factorizable contributions, and construct effective Feynman rules which can be used to compute next-to-eikonal emissions directly in the logarithm of the amplitude, finding agreement with earlier results obtained using path-integral methods. For cross sections, we also consider sub-eikonal corrections to the phase space for multiple soft-gluon emissions, which contribute to next-to-eikonal logarithms. To clarify the discussion, we examine a class of log(1 - x) terms in the Drell-Yan cross-section up to two loops. Our results are the first steps towards a systematic generalization of threshold resummations to next-to-leading power in the threshold expansion.