Theoretical uncertainties on αsfrom event-shape variables in e+e−annihilations

Jones, R. W. L.; Ford, M.; Salam, Gavin P.; Stenzel, H.; Wicke, D.

doi:10.1088/1126-6708/2003/12/007

Cited by 73 publications

(102 citation statements)

References 50 publications

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“…We shall adopt the envelope method, used for example in [63] as well as in many other works on resummation. This method takes the envelope of the curves obtained from each of several different sources of uncertainty estimate.…”

Section: Prescription For Estimating Total Uncertaintiesmentioning

confidence: 99%

NLL+NNLO predictions for jet-veto efficiencies in Higgs-boson and Drell-Yan production

Banfi

Salam

Zanderighi

2012

J. High Energ. Phys.

119

132

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Using the technology of the caesar approach to resummation, we examine the jet-veto efficiency in Higgs-boson and Drell-Yan production at hadron colliders and show that at next-to-leading logarithmic (NLL) accuracy the resummation reduces to just a Sudakov form factor. Matching with NNLO calculations results in stable predictions for the case of Drell-Yan production, but reveals substantial uncertainties in gluon-fusion Higgs production, connected in part with the poor behaviour of the perturbative series for the total cross section. We compare our results to those from powheg with and without reweighting by hqt, as used experimentally, and observe acceptable agreement. In an appendix we derive the part of the NNLL resummation corrections associated with the radius dependence of the jet algorithm.

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Section: Prescription For Estimating Total Uncertaintiesmentioning

confidence: 99%

NLL+NNLO predictions for jet-veto efficiencies in Higgs-boson and Drell-Yan production

Banfi

Salam

Zanderighi

2012

J. High Energ. Phys.

119

132

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“…The statistical error on α s is determined by variations around this minimum. The perturbative uncertainty is extracted with the uncertainty band method [31], exactly as in [11] for thrust. The envelope over the hard, matching, correlated and anti-correlated scale variations are included in this extraction.…”

Section: α S Extraction and Error Analysismentioning

confidence: 99%

Resummation of heavy jet mass and comparison to LEP data

Chien

Schwartz

2010

J. High Energ. Phys.

121

100

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The heavy jet mass distribution in e + e − collisions is computed to next-to-next-tonext-to leading logarithmic (N 3 LL) and next-to-next-to leading fixed order accuracy (NNLO). The singular terms predicted from the resummed distribution are confirmed by the fixed order distributions allowing a precise extraction of the unknown soft function coefficients. A number of quantitative and qualitative comparisons of heavy jet mass and the related thrust distribution are made. From fitting to ALEPH data, a value of α s is extracted, α s (m Z ) = 0.1220 ± 0.0031, which is larger than, but not in conflict with, the corresponding value for thrust. A weighted average of the two produces α s (m Z ) = 0.1193 ± 0.0027, consistent with the world average. A study of the non-perturbative corrections shows that the flat direction observed for thrust between α s and a simple non-perturbative shape parameter is not lifted in combining with heavy jet mass. The Monte Carlo treatment of hadronization gives qualitatively different results for thrust and heavy jet mass, and we conclude that it cannot be trusted to add power corrections to the event shape distributions at this accuracy. Whether a more sophisticated effective field theory approach to power corrections can reconcile the thrust and heavy jet mass distributions remains an open question.

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“…The larger of the deviations is taken as the systematic uncertainty. It was observed in [46,47] that systematic uncertainties determined from the differences between the PYTHIA, HERWIG, and ARI-ADNE models are generally much larger than those that arise from varying the parameters of a given model. Theoretical uncertainties: The theoretical calculation of event shape observables is a finite power series in α S .…”

Section: Fit Proceduresmentioning

confidence: 99%

Determination of α S using OPAL hadronic event shapes at $\sqrt{s} = 91\mbox{--}209~\mathrm{GeV}$ and resummed NNLO calculations

Abbiendi¹,

Ainsley²,

Åkesson³

et al. 2011

Eur. Phys. J. C

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Hadronic event shape distributions from e + e − annihilation measured by the OPAL experiment at centre-ofmass energies between 91 GeV and 209 GeV are used to determine the strong coupling α S . The results are based on QCD predictions complete to the next-to-next-to-leading order (NNLO), and on NNLO calculations matched to the resummed next-to-leading-log-approximation terms (NNLO+ NLLA). The combined NNLO result from all variables and centre-of-mass energies is The completeness of the NNLO and NNLO + NLLA results with respect to missing higher order contributions, studied by varying the renormalization scale, is improved compared to previous results based on NLO or NLO + NLLA predictions only. The observed energy dependence of α S agrees with the QCD prediction of asymptotic freedom and excludes the absence of running.

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Theoretical uncertainties on α_sfrom event-shape variables in e⁺e⁻annihilations

Cited by 73 publications

References 50 publications

NLL+NNLO predictions for jet-veto efficiencies in Higgs-boson and Drell-Yan production

NLL+NNLO predictions for jet-veto efficiencies in Higgs-boson and Drell-Yan production

Resummation of heavy jet mass and comparison to LEP data

Determination of α S using OPAL hadronic event shapes at $\sqrt{s} = 91\mbox{--}209~\mathrm{GeV}$ and resummed NNLO calculations

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