Reduction of one-loop amplitudes at the integrand level - NLO QCD calculations

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.Work supported by HEPTOOLS, MRTN-CT-2006-035505 and ALGOT OOLS, MTKD-CT-2004-014319