# Real and virtual photons within basis light-front quantization

## TL;DR

This paper uses Basis Light-Front Quantization to compute the internal structure of real and virtual photons in QED, achieving good agreement with experimental data and exploring the effects of photon virtuality.

## Contribution

It introduces a nonperturbative approach to calculate photon structure functions, TMDs, and GPDs within light-front QED, including virtual photons with nonzero mass.

## Key findings

- Good agreement with experimental photon structure function data
- Successful nonperturbative calculation of photon TMDs and GPDs
- Insights into virtual photon properties with nonzero mass

## Abstract

We compute the structure function, transverse momentum dependent parton distributions (TMDs), and generalized parton distributions (GPDs) for the physical photon from the light-front quantum electrodynamics (QED) Hamiltonian, determined for its constituent bare photon and electron-positron Fock components within the Basis Light-Front Quantization framework. After performing nonperturbative renormalization, we obtain a good quality description of the perturbative QED properties of the photon, as well as good agreement with the experimental data for the photon's structure function. We also investigate the TMDs and GPDs of the space-like and the time-like virtual photon by incorporating a nonzero photon mass.