One-loop corrections to light cone wave functions: the dipole picture DIS cross section

TL;DR

This paper develops a method for loop calculations in light cone perturbation theory with a helicity basis, enabling next-to-leading order accuracy in DIS cross section calculations within the dipole picture.

Contribution

It introduces a fully automatized approach for contracting tensor structures in loop integrals using a four-dimensional helicity scheme, validated by agreement with existing results.

Findings

Calculated one-loop correction to the photon to quark-antiquark wave function.

Achieved NLO accuracy for DIS cross section in the dipole formalism.

Confirmed regularization scheme independence of the cross section.

Abstract

We develop methods needed to perform loop calculations in light cone perturbation theory using a helicity basis, refining the method introduced in our earlier work. In particular this includes implementing a consistent way to contract the four-dimensional tensor structures from the helicity vectors with d-dimensional tensors arising from loop integrals, in a way that can be fully automatized. We demonstrate this explicitly by calculating the one-loop correction to the virtual photon to quark-antiquark dipole light cone wave function. This allows us to calculate the deep inelastic scattering cross section in the dipole formalism to next-to-leading order accuracy. Our results, obtained using the four dimensional helicity scheme, agree with the recent calculation by Beuf using conventional dimensional regularization, confirming the regularization scheme independence of this cross section.