EW corrections to $t \bar t$ distributions: the photon PDF effect

TL;DR

This paper investigates the impact of electroweak corrections, especially the photon PDF, on top-antitop distribution measurements at 13 TeV, comparing different photon PDF sets and exploring how top-pair rapidity can constrain the photon PDF.

Contribution

It provides a detailed comparison of EW corrections using NNPDF2.3QED and CT14QED photon PDFs at NLO accuracy for top-quark distributions, highlighting differences and potential constraints.

Findings

Photon PDF significantly affects top-quark distribution predictions.

Top-pair rapidity can be used to constrain the photon PDF.

Differences observed between NNPDF2.3QED and CT14QED sets.

Abstract

In this proceeding we present the impact of the EW corrections on $t \bar t$ distributions focusing on the effect of the photon PDF. We use the {\sc NNPDF2.3QED} and {\sc CT14QED} PDF sets, which include the photon PDF. We discuss a detailed comparison between the results obtained from these two PDF sets at NLO QCD+EW accuracy for 13 TeV, focusing on the top-quark $p_T$ and the top-quark pair rapidity. We point out the differences between these two PDF sets and we show that the rapidity of the top-quark pair can be used in order to constrain the photon PDF predicted by the {\sc NNPDF2.3QED} set.