NNLO QCD predictions of the electron charge asymmetry for the inclusive $pp \rightarrow W+X$ production in the forward region at 13 TeV and 14 TeV

TL;DR

This paper provides NNLO QCD predictions for the electron charge asymmetry in inclusive W production at 8, 13, and 14 TeV, comparing different PDFs and validating against 8 TeV LHCb data.

Contribution

First NNLO QCD calculations of electron charge asymmetry in forward W production at multiple LHC energies using various PDF sets.

Findings

NNLO predictions agree well with 8 TeV LHCb data.

Predicted charge asymmetry is sensitive to PDF differences at 14 TeV.

Predictions are consistent across different PDF models.

Abstract

This paper presents perturbative QCD predictions of the electron charge asymmetry for the inclusive $W^{\pm}+X \rightarrow e^{\pm} \nu +X$ production in proton-proton (pp) collisions. Perturbative QCD calculations are performed at next-to-next-to-leading order (NNLO) accuracy by using different parton distribution function (PDF) models at 8 TeV, 13 TeV, and 14 TeV center-of-mass energies of the CERN LHC pp collisions. The NNLO calculations are performed for the electrons to have transverse momentum more than 20 GeV in the forward electron pseudorapidity region $2.0 \leq \eta_{e} \leq 4.25$. The NNLO predictions are first compared at 8 TeV with the measurement of the LHCb experiment at the LHC for the W$^{+}$/W$^{-}$ cross section ratio and charge asymmetry distributions. The 8 TeV predictions using NNPDF3.1, CT14, and MMHT2014 PDF sets are reported to be in good agreement with the LHCb data for the entire $\eta_{e}$ region justifying the extension of the calculations to 13 TeV and 14 TeV energies. The charge asymmetry predictions at NNLO accuracy are also reported in the forward $\eta_{e}$ bins at 13 TeV and 14 TeV and compared among NNPDF3.1, CT14, and MMHT2014 PDF sets. Overall the predicted W$^{\pm}$ differential cross section and charge asymmetry distributions based on different PDF sets are found to be consistent with each other for the entire $\eta_{e}$ region. The charge asymmetry distributions are shown to be more sensitive to discriminate among different PDF models in the 14 TeV predictions.