Nested soft-collinear subtractions in NNLO QCD computations

Caola, Fabrizio (0000 0001 2156 142Xgrid.9132.9, CERN, Theoretical Physics Department, Geneva, Switzerland) (0000 0000 8700 0572grid.8250.f, IPPP, Durham University, Durham, UK) ; Melnikov, Kirill (0000 0001 0075 5874grid.7892.4, Institute for Theoretical Particle Physics, KIT, Karlsruhe, Germany) ; Röntsch, Raoul (0000 0001 0075 5874grid.7892.4, Institute for Theoretical Particle Physics, KIT, Karlsruhe, Germany)

18 April 2017

Abstract: We discuss a modification of the next-to-next-to-leading order (NNLO) subtraction scheme based on the residue-improved sector decomposition that reduces the number of double-real emission sectors from five to four. In particular, a sector where energies and angles of unresolved particles vanish in a correlated fashion is redundant and can be discarded. This simple observation allows us to formulate a transparent iterative subtraction procedure for double-real emission contributions, to demonstrate the cancellation of soft and collinear singularities in an explicit and (almost) process-independent way and to write the result of a NNLO calculation in terms of quantities that can be computed in four space-time dimensions. We illustrate this procedure explicitly in the simple case of O(αs2) gluonic corrections to the Drell–Yan process of qq¯ annihilation into a lepton pair. We show that this framework leads to fast and numerically stable computation of QCD corrections.


Published in: EPJC 77 (2017) 248
Published by: Springer/Società Italiana di Fisica
DOI: 10.1140/epjc/s10052-017-4774-0
License: CC-BY-3.0



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