Uncertainties on αS in global PDF analyses and implications for predicted hadronic cross sections
By Alan D. Martin, W. Stirling, R. Thorne, Graeme Watt. 2009
577 citations recorded by the source corpus.
AbstractWe determine the uncertainty on the strong coupling αS due to the experimental errors on the data fitted in global analysis of hard-scattering data, within the standard framework of leading-twist fixed-order collinear factorisation in the $\overline{\mathrm{MS}}$ scheme, finding that αS(MZ2)=0.1202−0.0015+0.0012 at next-to-leading order (NLO) and αS(MZ2)=0.1171−0.0014+0.0014 at next-to-next-to-leading order (NNLO). We do not address in detail the issue of the additional theory uncertainty on αS(MZ2), but an estimate is ±0.003 at NLO and at most ±0.002 at NNLO. We investigate the interplay between uncertainties on αS and uncertainties on parton distribution functions (PDFs). We show, for the first time, how both these sources of uncertainty can be accounted for simultaneously in calculations of cross sections, and we provide eigenvector PDF sets with different fixed αS values to allow further studies by the general user. We illustrate the application of these PDF sets by calculating cross sections for W, Z, Higgs boson and inclusive jet production at the Tevatron and LHC.
Subfields: Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/b98adde129620e9f6659a8c2fc9dd79859917f68
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Citations in the corpus
- Identification of b-quark jets with the CMS experiment (2012, methodology): “The uncertainties from the parton distribution functions (PDF) and the value of the strong coupling constant αS were estimated following the procedures from the MSTW2008 [12], CTEQ6.”
- A critical appraisal and evaluation of modern PDFs (2016, methodology): “0014 [231]”
- Les Houches 2013: Physics at TeV Colliders: Standard Model Working Group Report (2014, background): “error PDF sets [482], which are known to provide very close results to the PDF4LHC working group recommendation for the envelope prescription [218].”
- Progress in the Determination of the Partonic Structure of the Proton (2013, background): “The PDF uncertainties provided by MSTW and CT at the reference value of αS , and by NNPDF for all values of αS , do not include the αS uncertainty, though MSTW also provide additional sets allowing combined PDF+αS uncertainties [114].”
- Handbook of LHC Higgs Cross Sections: 3. Higgs Properties (2013, methodology): “HRESpredictions are computed with a factorization and renormalization scales set to125 GeV, and resummation scale set to 62.5 GeV, using the PDF set MSTW2008.”
- Search for production of vector-like quark pairs and of four top quarks in the lepton-plus-jets final state in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector (2015, methodology): “The single-top-quark samples are normalised to the approximate NNLO theoretical cross sections [105–107] calculated using the MSTW 2008 NNLO PDF set.”