Karlsruhe 2011 – scientific programme

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T: Fachverband Teilchenphysik

T 11: QCD (Theorie) II

T 11.1: Talk

Thursday, March 31, 2011, 16:45–17:00, 30.23: 10-1

Double hard QCD processes — •Daniel Ostermeier and Andreas Schäfer — Institut für Theoretische Physik, Universität Regensburg

To describe the so-called "underlying event" in collisions at LHC one has to substantially extent the techniques of collinear perturbative QCD. At these high energies multiple semi-hard reactions can occure in a single proton-proton collision at which point the transverse structure of hadrons (more precisely GPDs and generalized GPDs) becomes relevant. A distinct contribution from double-hard events was already isolated in cross sections measured at Tevatron long ago.

Based on earlier theory work, we have analysed in detail the double Drell-Yan process in proton-proton collisions, which seems to be the theoretically easiest process. This implied among other steps a generalization of the concept of soft factors from the case of standard single parton scattering to double hard processes. We give definitions of the soft factors for two parton distributions and present the results for corrections to the soft factors up to one-loop level in perturbation theory.
This work was supported by BMBF.