Strong coupling $\alpha_s(m_Z)$ extraction from a combined NNLO analysis of inclusive electroweak boson cross sections at hadron colliders

TL;DR

This paper extracts the strong coupling constant _s(m_Z) by comparing NNLO QCD predictions with 34 measurements of electroweak boson production at hadron colliders, achieving a precise determination.

Contribution

It presents a combined NNLO analysis of collider data to extract _s(m_Z), utilizing multiple PDF sets and identifying the most consistent results with the MMHT14 PDFs.

Findings

_s(m_Z) = 0.1188^{+0.0019}_{-0.0013} from combined fit

Good agreement between data and NNLO QCD predictions within uncertainties

MMHT14 PDFs provide the most consistent description of the data

Abstract

The inclusive cross sections of W$^+$, W$^-$, and Z boson production from 34 different measurements performed in proton-(anti)proton collisions at center-of-mass energies $\sqrt{s}$ = 1.8--13 TeV, are compared to perturbative QCD calculations at next-to-next-to-leading-order (NNLO) accuracy with four sets of parton distributions functions (CT14, HERAPDF2.0, MMHT14, and NNPDF3.0 PDFs) and varying values of the strong coupling constant at the Z mass pole, $\alpha_s(m_Z)$. The data-theory agreement is good within the experimental and theoretical uncertainties, with the CT14 and MMHT14 parton densities providing the most overall consistent description of all cross section data. A value of $\alpha_s(m_Z) = 0.1188^{+0.0019}_{-0.0013}$ is extracted from a combined fit of the 28 experimental LHC measurements to the corresponding NNLO theoretical predictions obtained with the MMHT14 PDF set, which provides the most robust and stable QCD coupling extraction of this analysis.