Tensor decomposition for bosonic and fermionic scattering amplitudes

TL;DR

This paper introduces a method to decompose complex multiloop scattering amplitudes into minimal, physically relevant form factors, simplifying calculations for both fermionic and bosonic particles in high-energy physics.

Contribution

It presents a new, general approach for decomposing multiloop multileg scattering amplitudes into Lorentz-invariant form factors, applicable to both fermionic and bosonic cases.

Findings

Applicable to four- and five-point amplitudes relevant for LHC physics

Identifies a minimal set of physically relevant form factors

Relates form factors to independent helicity amplitudes

Abstract

In this paper, we elaborate on a method to decompose multiloop multileg scattering amplitudes into Lorentz-invariant form factors, which exploits the simplifications that arise from considering four-dimensional external states. We propose a simple and general approach that applies to both fermionic and bosonic amplitudes and allows us to identify a minimal number of physically relevant form factors, which can be related one-to-one to the independent helicity amplitudes. We discuss explicitly its applicability to various four- and five-point scattering amplitudes relevant for LHC physics.