High-energy amplitudes and impact factors at next-to-leading order

TL;DR

This paper advances the understanding of high-energy scattering amplitudes by deriving the NLO corrections to the BK equation and calculating impact factors for virtual photons, enhancing precision in quantum chromodynamics predictions.

Contribution

It provides the first derivation of NLO impact factors and the NLO evolution equation for color dipoles in high-energy QCD.

Findings

Derived the NLO correction to the BK equation.

Calculated the impact factor for virtual photons in DIS at NLO.

Enhanced the theoretical framework for high-energy scattering amplitudes.

Abstract

To study scattering amplitudes at high-energy, the T-product of two currents can be expanded in terms of coefficient functions (impact factors) and matrix elements of ``composite color dipoles'' made of Wilson line operators with rapidity cutoff preserving conformal invariance. In the leading order, the high-energy evolution of color dipoles is governed by the non-linear Balitsky-Kovchegov (BK) equation. To describe the high-energy amplitudes in the next-to-leading order (NLO) one needs to know the coefficient function (``impact factor'') and the evolution of corresponding Wilson-line operators. Using the high-energy OPE, we find the next-to-leading order (NLO) correction to the BK equation and calculate the impact factor for virtual photons in deep inelastic scattering.