The Chirality-Flow Formalism for Standard Model Calculations

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 su(2 ) ⊕ 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