The fine structure constant

QED, Hadronic, and Electroweak Standard Model contributions to the muon anomalous magnetic moment, a µ ≡ (g µ − 2)/2, and their theoretical uncertainties are scrutinized. The status and implications of the recently reported 2.6 sigma experiment vs. theory deviation a exp µ − a SM µ = 426(165) × 10 −11 are discussed. Possible explanations due to supersymmetric loop effects with m SUSY ≃ 55 √ tan β GeV, radiative mass mechanisms at the 1-2 TeV scale and other "New Physics" scenarios are examined.

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“…(6). When simply averaged together, we find a exp µ (Average) = 116 592 023(151) × 10 −11 (CERN'77 + BNL'98 & '99).…”

Section: Introductionmentioning

confidence: 90%

“…with the prediction [2,3,4,5] a SM e = α 2π − 0.328 478 444 00 α π currently provides the best determination of the fine structure constant [6], α −1 (a e ) = 137.035 999 58 (52).…”

Section: Introductionmentioning

confidence: 97%

Muon anomalous magnetic moment: A harbinger for “new physics”

2001

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“…The nontrivial diagrams in higher orders were computed numerically [20,21]. The present value of the QED contribution to the muon anomalous magnetic moment reads [22,23] (as a review see [18])…”

Section: Introductionmentioning

confidence: 99%

An interpolation of the vacuum polarization function for the evaluation of hadronic contributions to the muon anomalous magnetic moment

2002

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We propose a simple parameterization of the two-point correlator of hadronic electromagnetic currents for the evaluation of the hadronic contributions to the muon anomalous magnetic moment. The parameterization is explicitly done in the Euclidean domain. The model function contains a phenomenological parameter which provides an infrared cutoff to guarantee the smooth behavior of the correlator at the origin in accordance with experimental data in e + e − annihilation. After fixing a numerical value for this parameter from the leading order hadronic contribution to the muon anomalous magnetic moment the next-to-leading order results related to the vacuum polarization function are accurately reproduced. The properties of the four-point correlator of hadronic electromagnetic currents as the so-called light-by-light scattering amplitude relevant for the calculation of the muon anomalous magnetic moment are briefly discussed.

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“…Although the computation of the higher order theory becomes more and more tedious, the necessity of the comparison with large-scale cosmological observations is a good reason to perform such computation as far as we can. One of the spectacular examples of the detailed comparison between perturbation theory and observations is the fine-structure constant in quantum electrodynamics (e.g., Kinoshita 1996). Our analysis in this paper will be extended to the third-order perturbation theory in a subsequent paper of the series.…”

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confidence: 97%

Statistics of Smoothed Cosmic Fields in Perturbation Theory. I. Formulation and Useful Formulae in Second‐Order Perturbation Theory

Matsubara¹

2003

ApJ

133

166

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We formulate a general method for perturbative evaluations of statistics of smoothed cosmic fields and provide useful formulae for application of the perturbation theory to various statistics. This formalism is an extensive generalization of the method used by Matsubara, who derived a weakly nonlinear formula of the genus statistic in a three-dimensional density field. After describing the general method, we apply the formalism to a series of statistics, including genus statistics, level-crossing statistics, Minkowski functionals, and a density extrema statistic, regardless of the dimensions in which each statistic is defined. The relation between the Minkowski functionals and other geometrical statistics is clarified. These statistics can be applied to several cosmic fields, including three-dimensional density field, three-dimensional velocity field, twodimensional projected density field, and so forth. The results are detailed for second-order theory of the formalism. The effect of the bias is discussed. The statistics of smoothed cosmic fields as functions of rescaled threshold by volume fraction are discussed in the framework of second-order perturbation theory. In CDMlike models, their functional deviations from linear predictions plotted against the rescaled threshold are generally much smaller than that plotted against the direct threshold. There is still a slight meatball shift against rescaled threshold, which is characterized by asymmetry in depths of troughs in the genus curve. A theory-motivated asymmetry factor in the genus curve is proposed.

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The fine structure constant

Cited by 99 publications

References 153 publications

Muon anomalous magnetic moment: A harbinger for “new physics”

Muon anomalous magnetic moment: A harbinger for “new physics”

An interpolation of the vacuum polarization function for the evaluation of hadronic contributions to the muon anomalous magnetic moment

Statistics of Smoothed Cosmic Fields in Perturbation Theory. I. Formulation and Useful Formulae in Second‐Order Perturbation Theory

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