The Anomalous Magnetic Moment of the Muon: A Theoretical Introduction

Knecht, Marc

doi:10.1007/978-3-540-44457-2_2

Cited by 47 publications

(32 citation statements)

References 170 publications

(294 reference statements)

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“…However, in this case the gap (9) is about 2.5 times larger than the SM weak contribution (10). The deviation (5) or the difference between (9) and (10) has a significance of about 2.4σ.…”

Section: Comparison Of Experiments and Standard Model Theorymentioning

confidence: 70%

“…We discuss the impact of the result for a µ on the SUSY parameter space and its relation to other relevant observables. The deviation ∆a µ (exp − SM) is positive and larger than the pure SM weak contribution, see (5), (9), (10). We have seen before that the MSSM can easily accommodate this deviation, preferably for a rather small SUSY mass scale and/or large tan β and a positive µ-parameter.…”

Section: Impact On Susy Phenomenologymentioning

confidence: 84%

“…[8][9][10][11][12] for recent reviews and references). The SM prediction can be decomposed into QED, hadronic and weak contributions.…”

Section: Comparison Of Experiments and Standard Model Theorymentioning

confidence: 99%

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The muon magnetic moment and supersymmetry

Stöckinger

2006

J. Phys. G: Nucl. Part. Phys.

292

340

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Abstract.The present review is devoted to the muon magnetic moment and its role in supersymmetry phenomenology. Analytical results for the leading supersymmetric one-and two-loop contributions are provided, numerical examples are given and the dominant tan β sign(µ)/M 2 SUSY behaviour is qualitatively explained. The consequences of the Brookhaven measurement are discussed. The 2σ deviation from the Standard Model prediction implies preferred ranges for supersymmetry parameters, in particular upper and lower mass bounds. Correlations with other observables from collider physics and cosmology are reviewed. We give, wherever possible, an intuitive understanding of each result before providing a detailed discussion.

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“…However, in this case the gap (9) is about 2.5 times larger than the SM weak contribution (10). The deviation (5) or the difference between (9) and (10) has a significance of about 2.4σ.…”

Section: Comparison Of Experiments and Standard Model Theorymentioning

confidence: 70%

Section: Impact On Susy Phenomenologymentioning

confidence: 84%

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The muon magnetic moment and supersymmetry

Stöckinger

2006

J. Phys. G: Nucl. Part. Phys.

292

340

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“…[301,302] (see also [303]), is not consistent with QCD. 32 The latter has a priori nothing to do with the full "quark loop" in QCD which is dual to the corresponding contribution in terms of hadronic degrees of freedom. Equation (201) tells us that at leading order in N c any model of QCD has to show the behavior a…”

Section: An Effective Field Theory Approach To Hadronic Light-by-lighmentioning

confidence: 99%

The muon g−2

2009

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The muon anomalous magnetic moment is one of the most precisely measured quantities in particle physics. In a recent experiment at Brookhaven it has been measured with a remarkable 14-fold improvement of the previous CERN experiment reaching a precision of 0.54ppm. Since the first results were published, a persisting "discrepancy" between theory and experiment of about 3 standard deviations is observed. It is the largest "established" deviation from the Standard Model seen in a "clean" electroweak observable and thus could be a hint for New Physics to be around the corner. This deviation triggered numerous speculations about the possible origin of the "missing piece" and the increased experimental precision animated a multitude of new theoretical efforts which lead to a substantial improvement of the prediction of the muon anomaly aµ = (gµ − 2)/2. The dominating uncertainty of the prediction, caused by strong interaction effects, could be reduced substantially, due to new hadronic cross section measurements in electron-positron annihilation at low energies. Also the recent electron g − 2 measurement at Harvard contributes substantially to the progress in this field, as it allows for a much more precise determination of the fine structure constant α as well as a cross check of the status of our theoretical understanding.In this report we review the theory of the anomalous magnetic moments of the electron and the muon. After an introduction and a brief description of the principle of the muon g − 2 experiment, we present a review of the status of the theoretical prediction and in particular discuss the role of the hadronic vacuum polarization effects and the hadronic light-by-light scattering correction, including a new evaluation of the dominant pion-exchange contribution. In the end, we find a 3.2 standard deviation discrepancy between experiment and Standard Model prediction. We also present a number of examples of how extensions of the electroweak Standard Model would change the theoretical prediction of the muon anomaly aµ. Perspectives for future developments in experiment and theory are briefly discussed and critically assessed. The muon g − 2 will remain one of the hot topics for further investigations.

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“…It is quite possible that a more precise measurement of the AMM of the free electron will result in a disagreement with the Standard Model. 17 In fact, the latest experimental (van Dyck 1987) and theoretical (Knecht 2003) results have increased the respective precisions from 0.03 to 0.004 ppm, or 930%, and from 0.17 to 0.021 ppm, or 830%, while increasing the accuracy between theory and experiment from 0.22 to 0.036 ppm, or 600%. Though not as large as in the case of the muon, the difference between the gain in precision and the gain in accuracy of the electron has increased the standard deviation from 1.2 to 1.7.…”

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confidence: 99%

On the Inherent Incompleteness of Scientific Theories

Mathen

2011

Act Nerv Super

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* __________________________________________________________________________________________We examine the question of whether scientific theories can ever be complete. For two closely related reasons, we will argue that they cannot. The first reason is the inability to determine what are "valid empirical observations", a result that is based on a self-reference Gödel/Tarski-like proof. The second reason is the existence of "meta-empirical" evidence of the inherent incompleteness of observations. These reasons, along with theoretical incompleteness, are intimately connected to the notion of belief and to theses within the philosophy of science: the Quine-Duhem (and underdetermination) thesis and the observational/theoretical distinction failure. Some puzzling aspects of the philosophical theses will become clearer in light of these connections. Other results that follow are: no absolute measure of the informational content of empirical data, no absolute measure of the entropy of physical systems, and no complete computer simulation of the natural world are possible. The connections with the mathematical theorems of Gödel and Tarski reveal the existence of other connections between scientific and mathematical incompleteness: computational irreducibility, complexity, infinity, arbitrariness and self-reference. Finally, suggestions will be offered of where a more rigorous (or formal) "proof" of scientific incompleteness can be found. __________________________________________________________________________________________Omnia olim mortua sunt itemur vivent.

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The Anomalous Magnetic Moment of the Muon: A Theoretical Introduction

Cited by 47 publications

References 170 publications

The muon magnetic moment and supersymmetry

The muon magnetic moment and supersymmetry

The muon g−2

On the Inherent Incompleteness of Scientific Theories

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