The chirality-flow formalism for standard model calculations

TL;DR

The paper introduces the chirality-flow formalism, a new method simplifying standard model calculations by representing Feynman diagrams with Lorentz-invariant spinor inner products, building on the spinor-helicity formalism.

Contribution

It presents the chirality-flow formalism as a novel, simplified approach for calculating scattering amplitudes in the standard model, extending previous work and making Feynman diagram computations more direct.

Findings

Chirality-flow formalism simplifies amplitude calculations.

Feynman diagrams are directly expressed in spinor inner products.

Method builds on and streamlines the spinor-helicity approach.

Abstract

Scattering amplitudes are often split up into their color (su(N)) and kinematic components. Since the su(N) gauge part can be described using flows of color, one may anticipate that the double su(2) kinematic part can be described in terms of flows of chirality. In two recent papers we showed that this is indeed the case, introducing the chirality-flow formalism for standard model calculations. Using the chirality-flow method -- which builds on and further simplifies the spinor-helicity formalism -- Feynman diagrams can be directly written down in terms of Lorentz-invariant spinor inner products, allowing the simplest and most direct path from a Feynman diagram to a complex number. In this presentation, we introduce this method and show some examples.