W- and Z-boson production with a massive bottom-quark pair at the Large Hadron Collider

TL;DR

This paper calculates total and differential cross sections for W and Z boson production with bottom-quark pairs at the LHC, including NLO QCD corrections and bottom-quark mass effects, highlighting the impact on theoretical uncertainties.

Contribution

It provides the first detailed NLO QCD analysis of W/Z + bottom-quark pair production including full bottom-quark mass effects at 14 TeV and 10 TeV.

Findings

NLO corrections reduce scale uncertainty for Zb anti-b production.

Wb anti-b production still has large scale uncertainties at NLO.

Mass effects are significant in certain kinematic regions.

Abstract

We present total and differential cross sections for W b anti-b and Z b anti-b production at the CERN Large Hadron Collider with a center-of-mass energy of 14 TeV, including Next-to-Leading Order (NLO) QCD corrections and full bottom-quark mass effects. We also provide numerical results obtained with a center-of-mass energy of 10 TeV. We study the scale uncertainty of the total cross sections due to the residual renormalization- and factorization-scale dependence of the truncated perturbative series. While in the case of Z b anti-b production the scale uncertainty of the total cross section is reduced by NLO QCD corrections, the W b anti-b production process at NLO in QCD still suffers from large scale uncertainties, in particular in the inclusive case. We also perform a detailed comparison with a calculation that considers massless bottom quarks, as implemented in the Monte Carlo program MCFM. The effects of a non-zero bottom-quark mass (m_b) cannot be neglected in phase-space regions where the relevant kinematic observable, such as the transverse momentum of the bottom quarks or the invariant mass of the bottom-quark pair, are of the order of m_b. The effects on the total production cross sections are usually smaller than the residual scale uncertainty at NLO in QCD.