Dresden 2013 – scientific programme

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T: Fachverband Teilchenphysik

T 12: QCD (Theorie) 2

T 12.7: Talk

Tuesday, March 5, 2013, 18:15–18:30, WIL-A120

A subtraction scheme for double-real radiation at NNLO — •David Heymes and Michal Czakon — RWTH Aachen University - Institut für Theoretische Teilchenphysik und Kosmologie, Aachen, Germany

Higher order perturbative calculations for QCD observables are indispensable to make precise predictions for the LHC. In each part of the calculation unphysical infrared divergences appear that cancel between real and virtual corrections to the cross section. While at next-to-leading order (NLO) general algorithms exist to subtract these singularities, further difficulties arise at next-to-next-to-leading order (NNLO) accuracy. A trivial generalization to this case is not possible. We present STRIPPER, a subtraction scheme for real radiation at NNLO. The main idea is to split the double-real radiation phase-space into sectors to obtain a Laurent series in the dimensional regulator є. The coefficients can be integrated numerically. This is achieved by parameterizing each sector adequately as well as exploiting the universal soft and collinear factorization properties of QCD tree-level matrix elements. This subtraction scheme can be implemented in the t’Hooft-Veltman regularization scheme, which will be discussed in this presentation.