Review of alpha_s determinations

Pich, Antonio

doi:10.22323/1.171.0022

Cited by 15 publications

(23 citation statements)

References 37 publications

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“…(19) in terms of α = α(a −1 ) using the renormalization group, where we define the QCD β-function as…”

Section: A Perturbative Ope With Tbcmentioning

confidence: 99%

“…Eqs. (19) - (23) are the most general parametrization of the 1/N 4 -effects for any lattice action using TBC.…”

Section: A Perturbative Ope With Tbcmentioning

confidence: 99%

“…For instance, precision determinations of the strong coupling constant α s from τ -meson decays rely on perturbative series that are also sensitive to the gluon condensate renormalon [18,19]. The same applies to computations of partial decay rates of a Higgs particle into heavy quark-antiquark pairs, see e.g.…”

Section: Introductionmentioning

confidence: 99%

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Perturbative expansion of the plaquette toO(α35)in four-dimensional SU(3) gauge theory

2014

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Using numerical stochastic perturbation theory, we determine the first 35 infinite volume coefficients of the perturbative expansion in powers of the strong coupling constant α of the plaquette in SU(3) gluodynamics. These coefficients are obtained in lattice regularization with the standard Wilson gauge action. The on-set of the dominance of the dimension four renormalon associated to the gluon condensate is clearly observed.We determine the normalization of the corresponding singularity in the Borel plane and convert this into the MS scheme. We also comment on the impact of the renormalon on non-perturbative determinations of the gluon condensate.

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“…(19) in terms of α = α(a −1 ) using the renormalization group, where we define the QCD β-function as…”

Section: A Perturbative Ope With Tbcmentioning

confidence: 99%

“…Eqs. (19) - (23) are the most general parametrization of the 1/N 4 -effects for any lattice action using TBC.…”

Section: A Perturbative Ope With Tbcmentioning

confidence: 99%

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Perturbative expansion of the plaquette toO(α35)in four-dimensional SU(3) gauge theory

2014

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“…The inclusive hadronic decay width of the τ lepton provides a clean source for the determination of α s at low energies [1,2,3,4]. The perturbative QCD contribution is known up to O(α 4 s ) [5] and the nonperturbative corrections are found to be small [6,7,8,9,10,11].…”

Section: Introductionmentioning

confidence: 99%

Determination of the Strong Coupling From Hadronic Tau Decays Using Renormalization Group Summed Perturbation Theory

2013

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We determine the strong coupling constant αs from the τ hadronic width using a renormalization group summed (RGS) expansion of the QCD Adler function. The main theoretical uncertainty in the extraction of αs is due to the manner in which renormalization group invariance is implemented, and the as yet uncalculated higher order terms in the QCD perturbative series. We show that new expansion exhibits good renormalization group improvement and the behaviour of the series is similar to that of the standard CIPT expansion. The value of the strong coupling in MS scheme obtained with the RGS expansion is αs(M 2 τ ) = 0.338 ± 0.010. The convergence properties of the new expansion can be improved by Borel transformation and analytic continuation in the Borel plane. This is discussed elsewhere in these proceedings.

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“…The hadronic decays of the τ lepton allow one of the most precise determinations of the strong coupling and provide also a beautiful experimental test of the predicted QCD running [1,2]. However, this process involves the strong coupling at a relatively low scale, where the theoretical ambiguities inherent to perturbative QCD are expected to be large.…”

Section: Introductionmentioning

confidence: 99%

Strong Coupling From the Tau Hadronic Width by Non-Power QCD Perturbation Theory

Caprini

2013

Mod. Phys. Lett. A

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Starting from the divergent character of the perturbative expansions in QCD and using the technique of series acceleration by the conformal mappings of the Borel plane, I define a novel, non-power perturbative expansion for the Adler function, which simultaneously implements renormalization-group summation and has a tamed large-order behaviour. The new expansion functions, which replace the standard powers of the coupling, are singular at the origin of the coupling plane and have divergent perturbative expansions, resembling the expanded function itself. Confronting the new perturbative expansions with the standard ones on specific models investigated recently in the literature, I show that they approximate in an impressive way the exact Adler function and the spectral function moments. Applied to the τ hadronic width, the contour-improved and the renormalization-group summed non-power expansions in the MS scheme lead to the prediction αs(M

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Review of alpha_s determinations

Cited by 15 publications

References 37 publications

Perturbative expansion of the plaquette toO(α35)in four-dimensional SU(3) gauge theory

Perturbative expansion of the plaquette toO(α35)in four-dimensional SU(3) gauge theory

Determination of the Strong Coupling From Hadronic Tau Decays Using Renormalization Group Summed Perturbation Theory

Strong Coupling From the Tau Hadronic Width by Non-Power QCD Perturbation Theory

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