A Numerical Unitarity Formalism for Evaluating One-Loop Amplitudes

Understand

Recent progress in unitarity techniques for one-loop scattering amplitudes makes a numerical implementation of this method possible.

• We present a 4-dimensional unitarity method for calculating the cut-constructible part of amplitudes and implement the method in a numerical procedure.
• Our technique can be applied to any one-loop scattering amplitude and offers the possibility that one-loop calculations can be performed in an automatic fashion, as tree-level amplitudes are currently done.
• Instead of individual Feynman diagrams, the ingredients for our one-loop evaluation are tree-level amplitudes, which are often already known.