Recursive generation of one-loop amplitudes in the Standard Model

Understand

We introduce the computer code Recola for the recursive generation of tree-level and one-loop amplitudes in the Standard Model.

• Tree-level amplitudes are constructed using off-shell currents instead of Feynman diagrams as basic building blocks.
• One-loop amplitudes are represented as linear combinations of tensor integrals whose coefficients are calculated similarly to the tree-level amplitudes by recursive construction of loop off-shell currents.
• We introduce a novel algorithm for the treatment of colour, assigning a colour structure to each off-shell current which enables us to recursively construct the colour structure of the amplitude efficiently.