PT Journal
AU Sborlini, GFR
   Driencourt-Mangin, F
   Hernandez-Pinto, RJ
   Rodrigo, G
TI Four-dimensional unsubtraction from the loop-tree duality
SO Journal of High Energy Physics
JI J. High Energy Phys.
PY 2016
BP 160
EP 42pp
VL 08
IS 8
DI 10.1007/JHEP08(2016)160
LA English
DE NLO Computations
AB We present a new algorithm to construct a purely four dimensional representation of higher-order perturbative corrections to physical cross-sections at next-to-leading order (NLO). The algorithm is based on the loop-tree duality (LTD), and it is implemented by introducing a suitable mapping between the external and loop momenta of the virtual scattering amplitudes, and the external momenta of the real emission corrections. In this way, the sum over degenerate infrared states is performed at integrand level and the cancellation of infrared divergences occurs locally without introducing subtraction counter-terms to deal with soft and final-state collinear singularities. The dual representation of ultraviolet counter-terms is also discussed in detail, in particular for self-energy contributions. The method is first illustrated with the scalar three-point function, before proceeding with the calculation of the physical cross-section for gamma* -> q (q) over bar (g), and its generalisation to multi-leg processes. The extension to next-to-next-to-leading order (NNLO) is briefly commented.
ER