Automating dipole subtraction

Abstract

We report on automating the Catani-Seymour dipole subtraction which is a general procedure to treat infrared divergences in real emission processes at next-to-leading order in QCD. The automatization rests on three essential steps: the creation of the dipole terms, the calculation of the color linked squared Born matrix elements, and the evaluation of different helicity amplitudes. The routines have been tested for a number of complex processes, such as the real emission process gg → ttggg.

Hadronic top-quark pair production in association with a hard jet at next-to-leading order QCD: phenomenological studies for the Tevatron and the LHC

“…Recently some effort has been invested to automatize this part of the calculation [83][84][85][86]. The results presented here may provide an interesting benchmark point for these attempts.…”

A comprehensive approach to new physics simulations

“…Quite amazingly, enormous progress has also been achieved very recently in the automatization of NLO computations. First the generation of the real corrections with the appropriate subtractions has been achieved in an automatic way [17][18][19][20][21][22]. Then several new algorithms for calculating loop amplitudes numerically have been proposed (see, e.g., [23] for a review) and some of them successfully applied to the computation of SM processes of physical interest [24][25][26].…”

AutoDipole – Automated generation of dipole subtraction terms –

“…The package (partial aspects of which have been discussed before [17,18]) consists of essentially three ingredients:…”

“…On the other hand, the method is completely algorithmic, thus an automation is feasible. This is a timely problem and its solution is the aim of the present work [17,18]. We note that it has recently also been addressed by other groups [19][20][21][22], see also [23].…”