Volume 365 - alphas-2019: Workshop on precision measurements of the QCD coupling constant (ALPHAS2019) - $a_S$ at hadron colliders
$a_S$ extraction from inclusive W and Z cross sections in pp collisions at the LHC
A. Poldaru,* D. d’Enterria, X. Weichen
*corresponding author
Full text: pdf
Pre-published on: 2019 July 22
Published on: 2019 September 13
Abstract
Twenty-eight different measurements of inclusive W±and Z cross sections in pp collisions at theLHC are compared to the corresponding theoretical predictions, at NNLO accuracy in perturba-tive QCD including NLO electroweak corrections, in order to extract the QCD coupling at theZ pole,αs(mZ). The theoretical cross sections are computed for four different parton distribution functions (PDFs): CT14, HERAPDF 2.0, MMHT14, and NNPDF 3.0. The calculated cross sections reproduce well the data within experimental and theoretical uncertainties. A linear fit of the αs dependence of the theoretical cross sections is used to extract the αs(mZ)value that best reproduces the measured cross sections. The 28αs(mZ)values extracted from each measurement are combined into a single result by properly taking into account their uncertainties and correlations. The following NNLO values of the QCD coupling for each one of the PDF sets are obtained:αs(mZ) =0.1181±0.0016 (CT14), 0.1209±0.0015 (MMHT14), and 0.1163±0.0019(NNPDF 3.0), with a final uncertainty at the 1.5% level, in good agreement with the αs(mZ)world average.
DOI: https://doi.org/10.22323/1.365.0013
Open Access