New Results on Threshold Resummation for QCD Hard Scattering

We introduce the relevant concepts necessary for the extension of threshold resummation for QCD hard scattering beyond the next-to-leading logarithmic (NLL) order. We consider two example processes. Firstly, dihadron production H1H2-->h1h2X at high invariant mass of the produced hadron pair. We take into account the color structure of the underlying partonic hard-scattering cross sections and determine the relevant hard and soft matrices in color space that contribute to the resummed cross section at next-to-next-to-leading logarithmic (NNLL) accuracy. We present numerical results for fixed-target and collider regimes. Secondly, we consider the cross section for single-inclusive jet production at large transverse momentum of the produced jet. Applying similar techniques, we deduce approximate fixed order results based on resummation. The accuracy of the threshold expansion may be determined by comparing to a recent full NNLO calculation for the all-gluon channel.