Determining the QCD coupling from lattice vacuum polarization

Hudspith, Renwick J.; Lewis, Randy; Maltman, Kim; Shintani, Eigo

doi:10.48550/arxiv.1510.04890

Cited by 4 publications

(4 citation statements)

References 10 publications

(12 reference statements)

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“…A further investigation of this method was initiated in Hudspith 15 [781] and completed by Hudspith 18 [780] (see also [782]) based on domain-wall fermion configurations at three lattice spacings, a −1 = 1.78, 2.38, 3.15 GeV, with three different light-quark masses on the two coarser lattices and one on the fine lattice. An extensive discussion of condensates, using continuum finite-energy sum rules was employed to estimate where their contributions might be negligible.…”

Section: Discussion Of Computationsmentioning

confidence: 99%

“…( 364) but with constant coefficients) no single condensate dominates and apparent convergence was poor for low Q 2 due to cancellations between contributions of similar size with alternating signs. (See, e.g., the list given by Hudspith 15 [781].) Choosing Q 2 to be at least ∼ 3.8 GeV 2 mitigated the problem, but then the coarsest lattice had to be discarded, due to large lattice artefacts.…”

Section: Discussion Of Computationsmentioning

confidence: 99%

“…The value of α 3 eff reaches α eff /(8π b 0 α eff ) and thus gives a • for perturbative behaviour. In Hudspith 15 [781] (superseded by…”

Section: Discussion Of Computationsmentioning

confidence: 99%

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FLAG Review 2021

Aoki

Blum²,

Colangelo³

et al. 2022

Eur. Phys. J. C

377

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We review lattice results related to pion, kaon, D-meson, B-meson, and nucleon physics with the aim of making them easily accessible to the nuclear and particle physics communities. More specifically, we report on the determination of the light-quark masses, the form factor $$f_+(0)$$ f + ( 0 ) arising in the semileptonic $$K \rightarrow \pi $$ K → π transition at zero momentum transfer, as well as the decay constant ratio $$f_K/f_\pi $$ f K / f π and its consequences for the CKM matrix elements $$V_{us}$$ V us and $$V_{ud}$$ V ud . Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of $$SU(2)_L\times SU(2)_R$$ S U ( 2 ) L × S U ( 2 ) R and $$SU(3)_L\times SU(3)_R$$ S U ( 3 ) L × S U ( 3 ) R Chiral Perturbation Theory. We review the determination of the $$B_K$$ B K parameter of neutral kaon mixing as well as the additional four B parameters that arise in theories of physics beyond the Standard Model. For the heavy-quark sector, we provide results for $$m_c$$ m c and $$m_b$$ m b as well as those for the decay constants, form factors, and mixing parameters of charmed and bottom mesons and baryons. These are the heavy-quark quantities most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. We review the status of lattice determinations of the strong coupling constant $$\alpha _s$$ α s . We consider nucleon matrix elements, and review the determinations of the axial, scalar and tensor bilinears, both isovector and flavor diagonal. Finally, in this review we have added a new section reviewing determinations of scale-setting quantities.

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Section: Discussion Of Computationsmentioning

confidence: 99%

Section: Discussion Of Computationsmentioning

confidence: 99%

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FLAG Review 2021

Aoki

Blum²,

Colangelo³

et al. 2022

Eur. Phys. J. C

377

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“…Data for ∆Π τ (Q 2 ) over a wide range of Euclidean Q 2 can be generated using the lattice, with an appropriate cylinder cut applied to avoid lattice artifacts at high Q 2 . This issue has been studied in detail for the ensemble employed here in a recent analysis focused on determining α s from lattice current-current two-point function data [11]. Here we first consider data at Q 2 high enough that [∆Π τ ] OPE will be safely dominated by its leading D = 2 and 4 contributions.…”

Section: Lattice and Continuum Investigations Of The Ope Representati...mentioning

confidence: 99%

A resolution of the inclusive flavor-breaking sum rule $\tau$ $V_{us}$ puzzle

Maltman¹,

Hudspith²,

Lewis³

et al. 2016

Proceedings of the 33rd International Symposium on Lattice Field Theory — PoS(LATTICE 2015)

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A combination of continuum and lattice methods is used to investigate systematic issues in the finite-energy-sum-rule determination of V us based on flavor-breaking combinations of hadronic τ decay data. Results for V us obtained using assumptions for D > 4 OPE contributions employed in previous conventional implementations of this approach are shown to display significant unphysical dependences on the choice of sum rule weight, w, and upper limit, s 0 , of the relevant experimental spectral integrals. Continuum and lattice results suggest the necessity of a new implementation of the flavor-breaking sum rule approach, in which not only |V us |, but also D > 4 effective condensates are fit to data. Lattice results also provide a means of quantifying the truncation error for the slowly converging D = 2 OPE series. The new implementation is shown to produce |V us | results free of unphysical s 0 -and w-dependences and typically ∼ 0.0020 higher than the (unstable) results found using the conventional implementation. With preliminary new experimental results for the Kπ branching fraction, the resulting |V us | is in excellent agreement with that obtained from K ℓ3 , and compatible within errors with expectations from three-family unitarity.

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