Reduction of one-loop amplitudes at the integrand level - NLO QCD calculations Ossola, Giovanni Papadopoulos, Costas G. Pittau, Roberto Jet cross-sections General algorithm Presented by C.G. Papadopulos at the Cracow Epiphany Confer ence on LHC Physics, Cracow, Poland, 4–6 January 2008. The recently proposed method (OPP) to extract the coefficients of the scalar one-loop integrals to any multi-particle (sub)-amplitude is described. Within this method no analytical information on the structure of the amplitude is needed, allowing for a purely numerical, but still algebraic, implementation of the algorithm. The algorithm can be used to automatically perform one-loop calculation both in QCD and in the EW Theory. As an application, we give QCD one-loop results for the process pp → ZZZ at the LHC. 2014-07-28T11:00:50Z 2014-07-28T11:00:50Z 2008 journal article Ossola, G.; Papadopoulos, C.G.; Pittau, R. Reduction of one-loop amplitudes at the integrand level - NLO QCD calculations. Acta Physica Polonica B, 39(7): 1685-1693 (2008). [http://hdl.handle.net/10481/32797] 0587-4254 http://hdl.handle.net/10481/32797 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ open access Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License Jagiellonian University