Parton Distributions and Event Generators

TL;DR

This paper introduces a new set of parton distributions with QED corrections implemented in Pythia8, enabling improved simulations of photon-initiated processes in collider phenomenology.

Contribution

The paper develops and integrates a leading-order NNPDF2.3QED PDF set with QED corrections into Pythia8, and explores its phenomenological implications.

Findings

The NNPDF2.3QED LO set is consistent with higher-order PDFs.

Photon-initiated contributions significantly affect dilepton production.

Implementation enhances collider event simulations.

Abstract

We present the implementation within the Pythia8 event generator of a set of parton distributions based on NNPDF methodology. We construct a set of leading-order parton distributions with QED corrections, NNPDF2.3QED LO set, based on the same data as the previous NNPDF2.3 NLO and NNLO PDF sets. We compare this PDF set to its higher-order counterparts, we discuss its implementation as an internal set in Pythia8, and we use it to study some of the phenomenological implications of photon-initiated contributions for dilepton production at hadron colliders.