Precision NNLO determination of alpha_s(M_Z) using an unbiased global parton set

Richard D. Ball, Valerio Bertone, Luigi Del Debbio, Stefano Forte, Alberto Guffanti, Jose I. Latorre, Simone Lionetti, Juan Rojo, Maria Ubiali

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

We determine the strong coupling alpha_s at NNLO in perturbative QCD using the global dataset input to the NNPDF2.1 NNLO parton fit: data from neutral and charged current deep-inelastic scattering, Drell-Yan, vector boson production and inclusive jets. We find alpha_s(M_Z)=0.1173+- 0.0007 (stat), where the statistical uncertainty comes from the underlying data and uncertainties due to the analysis procedure are negligible. We show that the distribution of alpha_s values preferred by different experiments in the global fit is statistically consistent, without need for rescaling uncertainties by a "tolerance" factor. We show that if deep-inelastic data only are used, the best-fit value of alpha_s is somewhat lower, but consistent within one sigma with the global determination. We estimate the dominant theoretical uncertainty, from higher orders corrections, to be Delta alpha_s (pert) ~ 0.0009.
Original languageEnglish
Pages (from-to)66-71
JournalPhysics Letters B
Volume707
Issue number1
DOIs
Publication statusPublished - 16 Jan 2012

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neutral currents
partons
inelastic scattering
bosons
quantum chromodynamics
estimates

Bibliographical note

11 pages, 6 figures. Various small corrections and improvements: Chi2 values for PDF fits provided, discussion of pulls clarified. Final version, to be published in Phys.Lett.B

Keywords

  • hep-ph

Cite this

Ball, R. D., Bertone, V., Debbio, L. D., Forte, S., Guffanti, A., Latorre, J. I., ... Ubiali, M. (2012). Precision NNLO determination of alpha_s(M_Z) using an unbiased global parton set. Physics Letters B, 707(1), 66-71. https://doi.org/10.1016/j.physletb.2011.11.053
Ball, Richard D. ; Bertone, Valerio ; Debbio, Luigi Del ; Forte, Stefano ; Guffanti, Alberto ; Latorre, Jose I. ; Lionetti, Simone ; Rojo, Juan ; Ubiali, Maria. / Precision NNLO determination of alpha_s(M_Z) using an unbiased global parton set. In: Physics Letters B. 2012 ; Vol. 707, No. 1. pp. 66-71.
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Ball, RD, Bertone, V, Debbio, LD, Forte, S, Guffanti, A, Latorre, JI, Lionetti, S, Rojo, J & Ubiali, M 2012, 'Precision NNLO determination of alpha_s(M_Z) using an unbiased global parton set' Physics Letters B, vol. 707, no. 1, pp. 66-71. https://doi.org/10.1016/j.physletb.2011.11.053

Precision NNLO determination of alpha_s(M_Z) using an unbiased global parton set. / Ball, Richard D.; Bertone, Valerio; Debbio, Luigi Del; Forte, Stefano; Guffanti, Alberto; Latorre, Jose I.; Lionetti, Simone; Rojo, Juan; Ubiali, Maria.

In: Physics Letters B, Vol. 707, No. 1, 16.01.2012, p. 66-71.

Research output: Contribution to JournalArticleAcademicpeer-review

TY - JOUR

T1 - Precision NNLO determination of alpha_s(M_Z) using an unbiased global parton set

AU - Ball, Richard D.

AU - Bertone, Valerio

AU - Debbio, Luigi Del

AU - Forte, Stefano

AU - Guffanti, Alberto

AU - Latorre, Jose I.

AU - Lionetti, Simone

AU - Rojo, Juan

AU - Ubiali, Maria

N1 - 11 pages, 6 figures. Various small corrections and improvements: Chi2 values for PDF fits provided, discussion of pulls clarified. Final version, to be published in Phys.Lett.B

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N2 - We determine the strong coupling alpha_s at NNLO in perturbative QCD using the global dataset input to the NNPDF2.1 NNLO parton fit: data from neutral and charged current deep-inelastic scattering, Drell-Yan, vector boson production and inclusive jets. We find alpha_s(M_Z)=0.1173+- 0.0007 (stat), where the statistical uncertainty comes from the underlying data and uncertainties due to the analysis procedure are negligible. We show that the distribution of alpha_s values preferred by different experiments in the global fit is statistically consistent, without need for rescaling uncertainties by a "tolerance" factor. We show that if deep-inelastic data only are used, the best-fit value of alpha_s is somewhat lower, but consistent within one sigma with the global determination. We estimate the dominant theoretical uncertainty, from higher orders corrections, to be Delta alpha_s (pert) ~ 0.0009.

AB - We determine the strong coupling alpha_s at NNLO in perturbative QCD using the global dataset input to the NNPDF2.1 NNLO parton fit: data from neutral and charged current deep-inelastic scattering, Drell-Yan, vector boson production and inclusive jets. We find alpha_s(M_Z)=0.1173+- 0.0007 (stat), where the statistical uncertainty comes from the underlying data and uncertainties due to the analysis procedure are negligible. We show that the distribution of alpha_s values preferred by different experiments in the global fit is statistically consistent, without need for rescaling uncertainties by a "tolerance" factor. We show that if deep-inelastic data only are used, the best-fit value of alpha_s is somewhat lower, but consistent within one sigma with the global determination. We estimate the dominant theoretical uncertainty, from higher orders corrections, to be Delta alpha_s (pert) ~ 0.0009.

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Ball RD, Bertone V, Debbio LD, Forte S, Guffanti A, Latorre JI et al. Precision NNLO determination of alpha_s(M_Z) using an unbiased global parton set. Physics Letters B. 2012 Jan 16;707(1):66-71. https://doi.org/10.1016/j.physletb.2011.11.053