We present a determination of the strong coupling constant αs(mZ) based on the NNPDF3.1 determination of parton distributions, which for the first time includes constraints from jet production, top-quark pair differential distributions, and the ZpTdistributions using exact NNLO theory. Our result is based on a novel extension of the NNPDF methodology – the correlated replica method – which allows for a simultaneous determination of αsand the PDFs with all correlations between them fully taken into account. We study in detail all relevant sources of experimental, methodological and theoretical uncertainty. At NNLO we find αs(mZ) = 0.1185 ± 0. 0005(exp)± 0. 0001(meth), showing that methodological uncertainties are negligible. We conservatively estimate the theoretical uncertainty due to missing higher order QCD corrections (N3LO and beyond) from half the shift between the NLO and NNLO αsvalues, finding Δαsth=0.0011.

Precision determination of the strong coupling constant within a global PDF analysis: NNPDF Collaboration / R.D. Ball, S. Carrazza, L.D. Debbio, S. Forte, Z. Kassabov, J. Rojo, E. Slade, M. Ubiali. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - 78:5(2018 May 24). [10.1140/epjc/s10052-018-5897-7]

Precision determination of the strong coupling constant within a global PDF analysis: NNPDF Collaboration

S. Carrazza;S. Forte
;
Z. Kassabov;
2018

Abstract

We present a determination of the strong coupling constant αs(mZ) based on the NNPDF3.1 determination of parton distributions, which for the first time includes constraints from jet production, top-quark pair differential distributions, and the ZpTdistributions using exact NNLO theory. Our result is based on a novel extension of the NNPDF methodology – the correlated replica method – which allows for a simultaneous determination of αsand the PDFs with all correlations between them fully taken into account. We study in detail all relevant sources of experimental, methodological and theoretical uncertainty. At NNLO we find αs(mZ) = 0.1185 ± 0. 0005(exp)± 0. 0001(meth), showing that methodological uncertainties are negligible. We conservatively estimate the theoretical uncertainty due to missing higher order QCD corrections (N3LO and beyond) from half the shift between the NLO and NNLO αsvalues, finding Δαsth=0.0011.
engineering (miscellaneous); physics and astronomy (miscellaneous)
Settore FIS/02 - Fisica Teorica, Modelli e Metodi Matematici
Settore FIS/04 - Fisica Nucleare e Subnucleare
   Proton strucure for discovery at the Large Hadron Collider (NNNPDF)
   NNNPDF
   EUROPEAN COMMISSION
   H2020
   740006
24-mag-2018
Article (author)
File in questo prodotto:
File Dimensione Formato  
nnpdf31alphas.pdf

accesso aperto

Tipologia: Post-print, accepted manuscript ecc. (versione accettata dall'editore)
Dimensione 729.08 kB
Formato Adobe PDF
729.08 kB Adobe PDF Visualizza/Apri
Ball2018_Article_PrecisionDeterminationOfTheStr.pdf

accesso aperto

Tipologia: Publisher's version/PDF
Dimensione 1.11 MB
Formato Adobe PDF
1.11 MB Adobe PDF Visualizza/Apri
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/579798
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 45
  • ???jsp.display-item.citation.isi??? 39
social impact