The anomalous magnetic moment of the electron and the quantum electrodynamics determination of the fine-structure constant

1987 ◽  
Vol IM-36 (2) ◽  
pp. 201-204 ◽  
Author(s):  
Toichiro Kinoshita
Keyword(s):  
Fine Structure ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Quantum Electrodynamics ◽  
Structure Constant ◽  
Fine Structure Constant

scholarly journals Theory of the Anomalous Magnetic Moment of the Electron

Atoms ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 28 ◽  
Author(s):  
Tatsumi Aoyama ◽  
Toichiro Kinoshita ◽  
Makiko Nio
Keyword(s):  
Fine Structure ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Quantum Electrodynamics ◽  
Penning Trap ◽  
Weak Interactions ◽  
Perturbation Expansion ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Best Value

The anomalous magnetic moment of the electron a e measured in a Penning trap occupies a unique position among high precision measurements of physical constants in the sense that it can be compared directly with the theoretical calculation based on the renormalized quantum electrodynamics (QED) to high orders of perturbation expansion in the fine structure constant α , with an effective parameter α / π . Both numerical and analytic evaluations of a e up to ( α / π ) 4 are firmly established. The coefficient of ( α / π ) 5 has been obtained recently by an extensive numerical integration. The contributions of hadronic and weak interactions have also been estimated. The sum of all these terms leads to a e ( theory ) = 1 159 652 181.606 ( 11 ) ( 12 ) ( 229 ) × 10 − 12 , where the first two uncertainties are from the tenth-order QED term and the hadronic term, respectively. The third and largest uncertainty comes from the current best value of the fine-structure constant derived from the cesium recoil measurement: α − 1 ( Cs ) = 137.035 999 046 ( 27 ) . The discrepancy between a e ( theory ) and a e ( ( experiment ) ) is 2.4 σ . Assuming that the standard model is valid so that a e (theory) = a e (experiment) holds, we obtain α − 1 ( a e ) = 137.035 999 1496 ( 13 ) ( 14 ) ( 330 ) , which is nearly as accurate as α − 1 ( Cs ) . The uncertainties are from the tenth-order QED term, hadronic term, and the best measurement of a e , in this order.

scholarly journals Precision spectroscopy of atomic helium

2020 ◽  
Vol 7 (12) ◽  
pp. 1818-1827
Author(s):  
Yu R Sun ◽  
Shui-Ming Hu
Keyword(s):  
Fine Structure ◽  
Quantum Electrodynamics ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Nuclear Charge Radius ◽  
Precision Spectroscopy ◽  
Structure Splitting ◽  
Three Body ◽  
Atomic Helium

Abstract Helium is a prototype three-body system and has long been a model system for developing quantum mechanics theory and computational methods. The fine-structure splitting in the 23P state of helium is considered to be the most suitable for determining the fine-structure constant α in atoms. After more than 50 years of efforts by many theorists and experimentalists, we are now working toward a determination of α with an accuracy of a few parts per billion, which can be compared to the results obtained by entirely different methods to verify the self-consistency of quantum electrodynamics. Moreover, the precision spectroscopy of helium allows determination of the nuclear charge radius, and it is expected to help resolve the ‘proton radius puzzle’. In this review, we introduce the latest developments in the precision spectroscopy of the helium atom, especially the discrepancies among theoretical and experimental results, and give an outlook on future progress.

Introductory remarks

1982 ◽  
Vol 304 (1482) ◽  
pp. 3-4
Keyword(s):  
World War Ii ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Quantum Electrodynamics ◽  
Power Series Expansion ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Abelian Gauge

The title of this meeting, which refers to gauge theories, could equivalently have specified renormalizable quantum field theories. The first quantum field theory arose from the quantization by Dirac, Heisenberg and Pauli of Maxwell’s classical theory of electromagnetism. This immediately revealed the basic problem that although the smallness of the fine-structure constant appeared to give an excellent basis for a power-series expansion, corrections to lowest order calculations gave meaningless infinite results. Quantum electrodynamics (QED ) is, of course, an Abelian gauge theory, and the first major triumph o f fundamental physics after World War II was the removal of the infinities from the theory by the technique of renormalization developed by Schwinger, Feynman and Dyson, stimulated by the measurement of the Lamb shift and the anomalous magnetic moment of the electron. In the intervening years, especially through the beautiful experiments at Cern on the anomalous magnetic moment of the muon, the agreement between this theory and experiment has been pushed to the extreme technical limits of both measurement and calculation.

scholarly journals State of the art in the determination of the fine structure constant: test of Quantum Electrodynamics and determination of h/mu

2013 ◽  
Vol 525 (7) ◽  
pp. 484-492 ◽  
Author(s):  
Rym Bouchendira ◽  
Pierre Cladé ◽  
Saida Guellati-Khélifa ◽  
Francois Nez ◽  
Francois Biraben
Keyword(s):  
Fine Structure ◽  
Quantum Electrodynamics ◽  
State Of The Art ◽  
Structure Constant ◽  
Fine Structure Constant

scholarly journals New Determination of the Fine Structure Constant and Test of the Quantum Electrodynamics

2011 ◽  
Vol 106 (8) ◽  
Author(s):  
Rym Bouchendira ◽  
Pierre Cladé ◽  
Saïda Guellati-Khélifa ◽  
François Nez ◽  
François Biraben
Keyword(s):  
Fine Structure ◽  
Quantum Electrodynamics ◽  
Structure Constant ◽  
Fine Structure Constant

scholarly journals An Investigation Into The Mathematical and Physical Origins of The Fine-Structure Constant

2021 ◽  
Author(s):  
Lamont Williams
Keyword(s):  
Fine Structure ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Quantum Physics ◽  
Ad Hoc ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Quantum Mechanical ◽  
The Standard Model ◽  
Corrective Term

Abstract The fine-structure constant, α, unites fundamental aspects of electromagnetism, quantum physics, and relativity. As such, it is one of the most important constants in nature. However, why it has the value of approximately 1/137 has been a mystery since it was first identified more than 100 years ago. To date, it is an ad hoc feature of the Standard Model, as it does not appear to be derivable within that body of work — being determined solely by experimentation. This report presents a mathematical formula for α that results in an exact match with the currently accepted value of the constant. The formula requires that a simple corrective term be applied to the value of one of the factors in the suggested equation. Notably, this corrective term, at approximately 0.023, is similar in value to the electron anomalous magnetic moment value, at approximately 0.0023, which is the corrective term that needs to be applied to the g-factor in the equation for the electron spin magnetic moment. In addition, it is shown that the corrective term for the proposed equation for α can be derived from the anomalous magnetic moment values of the electron, muon, and tau particle — values that have been well established through theory and/or experimentation. This supports the notion that the corrective term for the α formula is also a real and natural quantity. The quantum mechanical origins of the lepton anomalous magnetic moment values suggest that there might be a quantum mechanical origin to the corrective term for α as well. This possibility, as well as a broader physical interpretation of the value of α, is explored.

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