A numerical implementation of the chirality-flow formalism

Abstract: The chirality-flow formalism has proven to make amplitude calculations in the Standard Model analytically simple in comparison to previously established formalisms. To test the viability of the chirality-flow formalism for numerical implementations, a Chiral Automized Flow Extension (CAFE) for MadGraph5_aMC@NLO has been developed to compare amplitude evaluation time scaling between the two. CAFE uses a new UFO format model and a new HELAS-like library to make evaluations in the chirality-flow formalism. Additionally, an algorithm has been implemented to make a simple gauge choice, based on which diagrams that will not contribute to the matrix elements will be discarded already at compile time. The effects of these two changes on evaluation time scaling with process complexity have been studied, and CAFE has been shown to both be faster for all considered processes and to scale better with diagram complexity than MadGraph5.