The partonic structure of the electron at the next-to-leading logarithmic accuracy in QED

TL;DR

This paper computes the unpolarised electron, positron, and photon parton distribution functions in QED at next-to-leading logarithmic accuracy, providing both analytical and numerical results crucial for high-precision cross section calculations.

Contribution

It introduces the first comprehensive calculation of electron, positron, and photon PDFs in QED at NLL accuracy, including analytical formulas and numerical validation.

Findings

Excellent agreement between analytical and numerical results

Additive formula matching large-$z$ and small-$z$ solutions

Includes all orders in the QED coupling for large-$z$

Abstract

By working in QED, we obtain the electron, positron, and photon Parton Distribution Functions (PDFs) of the unpolarised electron at the next-to-leading logarithmic accuracy. The PDFs account for all of the universal effects of initial-state collinear origin, and are key ingredients in the calculations of cross sections in the so-called structure-function approach. We present both numerical and analytical results, and show that they agree extremely well with each other. The analytical predictions are defined by means of an additive formula that matches a large-$z$ solution that includes all orders in the QED coupling constant $\alpha$, with a small- and intermediate-$z$ solution that includes terms up to ${\cal O}(\alpha^3)$.