Scattering amplitudes for high-energy factorization

TL;DR

This paper introduces a method to construct gauge-invariant scattering amplitudes with off-shell gluons, enabling efficient calculations for high-energy processes beyond traditional collinear factorization.

Contribution

It provides a new prescription for calculating gauge-invariant tree-level amplitudes with off-shell initial gluons for arbitrary final states, facilitating automation and broader applicability.

Findings

Allows construction of gauge-invariant amplitudes with off-shell gluons.

Applicable to processes with arbitrary final states.

Enhances calculations in high-energy factorization schemes.

Abstract

A prescription is presented to construct manifestly gauge invariant tree-level scattering amplitudes with one or two off-shell initial-state gluons for processes with arbitrary particles in the final state, which allows for calculations that are efficient and easy to automate. These scattering amplitudes are relevant for factorization schemes beyond collinear factorization that allow the gluons entering the partonic cross section to have non-vanishing transversal momentum components.