scholarly journals Applications of the Infinite Momentum Method to Quantum Electrodynamics and Bound State Problems

1973 ◽  
Author(s):  
Stanley J. Brodsky
Keyword(s):  
Quantum Electrodynamics ◽  
Bound State

Quadronium and quantum electrodynamics

1996 ◽  
Vol 74 (7-8) ◽  
pp. 527-533 ◽  
Author(s):  
James J. Griffin
Keyword(s):  
Quantum Electrodynamics ◽  
Composite Particle ◽  
Bound State ◽  
Heavy Ion ◽  
Annihilation Rate ◽  
Small Correction ◽  
Order Matrix Element ◽  
Nucleus Scattering ◽  
Electron Magnetic Moment ◽  
Rule Out

The composite-particle scenario is a phenomenology that can organize the data of the "sharp lepton problem" posed by heavy-ion and (β+ + atom) studies. It hypothesizes a new composite particle (of mass ~3mc2) as the source of the observed sharp energy (e+e−) decay pairs. Available data rule out the possibilities that the source is a new elementary particle or that it is a quasi-bound state of (e+e−). Occam's razor therefore currently favors the quadronium structure, Q0 = (e+e+e−e−). Implications of quadronium for high-precision quantum electrodynamics (QED) are considered, and calculated and (or) measured deviations in QED that are sensitive to the existence of Q0 are identified. In particular, for the electron magnetic-moment anomaly, a(e) = (ge − 2)/2, a Q0–pole effects a small correction to the contributions of O(α4), which is therefore small compared to the largest current (theoretical) uncertainty. For photon–photon scattering, Q0 corrects the leading order matrix element, and allows resonant Q0 creation in photon–nucleus scattering. Finally, a Q0 bound state corrects the O(α) correction to the leading 3γ annihilation rate of triplet positronium. Therefore Q0 may contribute significantly to this decay rate, which is currently in a 10σ discrepancy with experiment. A current experimental gap is the lack of corroborative data on the sharp (Γ ≤ 2.1 keV) 330.1 keV electrons reported by Sakai from irradiations of U and Th with β+-decay positrons. A study of these (and (or) their expected partner positrons of the same energy) in collisions of (~3 MeV) beam positrons (or electrons) upon high-Z neutral atoms could fill this gap. Similar studies with positrons of 660–795 keV would test the expectation that recoilless resonance creation of the Q0 source of these pairs is also possible.

Gyromagnetic factors of bound particles with arbitrary spin in quantum electrodynamics

2002 ◽  
Vol 80 (11) ◽  
pp. 1365-1372
Author(s):  
R N Faustov ◽  
A P Martynenko
Keyword(s):  
Hydrogen Atom ◽  
Magnetic Moment ◽  
Quantum Electrodynamics ◽  
Bound State ◽  
Arbitrary Spin ◽  
Radiative Corrections ◽  
Particle Spin ◽  
G Factors

A quasipotential method is formulated for calculating relativistic and radiative corrections to the magnetic moment of a two-particle bound state in the case of particles with arbitrary spin. It is shown that the g factors of bound particles contain O(α2) terms depending on the particle spin. Numerical values for the g factors of the electron in the hydrogen atom and deuterium are obtained. PACS Nos.: 31.30Jv, 12.20Ds, 32.10Dk

The muonic hydrogen Lamb-shift experiment

2005 ◽  
Vol 83 (4) ◽  
pp. 339-349 ◽  
Author(s):  
R Pohl ◽  
A Antognini ◽  
F D Amaro ◽  
F Biraben ◽  
J MR Cardoso ◽  
...  
Keyword(s):  
Charge Radius ◽  
Quantum Electrodynamics ◽  
Lamb Shift ◽  
Laser System ◽  
Bound State ◽  
Muonic Hydrogen ◽  
X Rays ◽  
Large Area ◽  
Proton Charge ◽  
Proton Charge Radius

The charge radius of the proton, the simplest nucleus, is known from electron-scattering experiments only with a surprisingly low precision of about 2%. The poor knowledge of the proton charge radius restricts tests of bound-state quantum electrodynamics (QED) to the precision level of about 6 × 10–6, although the experimental data themselves (1S Lamb shift in hydrogen) have reached a precision of 2 × 10–6. The determination of the proton charge radius with an accuracy of 10–3 is the main goal of our experiment, opening a way to check bound-state QED predictions to a level of 10–7. The principle is to measure the 2S–2P energy difference in muonic hydrogen (µ–p) by infrared laser spectroscopy. The first data were taken in the second half of 2003. Muons from our unique very-low-energy muon beam are stopped at a rate of ~100 s–1 in 0.6 mbar H2 gas where the lifetime of the formed µp(2S) atoms is about 1.3 µs. An incoming muon triggers a pulsed multistage laser system that delivers ~0.2 mJ at λ ≈ 6 µm. Following the laser excitation µp(2S) → µp(2P) we observe the 1.9 keV X-rays from 2P–1S transitions using large area avalanche photodiodes. The resonance frequency, and, hence, the Lamb shift and the proton radius, is determined by measuring the intensity of these X-rays as a function of the laser wavelength. A broad range of laser frequencies was scanned in 2003 and the analysis is currently under way. PACS Nos.: 36.10.Dr, 14.20.Dh, 42.62.Fi

scholarly journals Some recent advances in bound-state quantum electrodynamics

2005 ◽  
Vol 83 (4) ◽  
pp. 375-386 ◽  
Author(s):  
U D Jentschura ◽  
J Evers
Keyword(s):  
Effective Field Theories ◽  
Quantum Electrodynamics ◽  
Lamb Shift ◽  
Recent Progress ◽  
Bound State ◽  
Effective Field ◽  
Field Theories ◽  
Nonrelativistic Quantum ◽  
Self Energy ◽  
Bound Electron

We discuss recent progress in various problems related to bound-state quantum electrodynamics: the bound-electron g factor, two-loop self-energy corrections, and the laser-dressed Lamb shift. The progress relies on various advances in the bound-state formalism, including ideas inspired by effective field theories such as nonrelativistic quantum electrodynamics. Radiative corrections in dynamical processes represent a promising field for further investigations. PACS Nos.: 31.15.–p, 12.20.Ds

scholarly journals New precise measurements of muonium hyperfine structure at J-PARC MUSE

2019 ◽  
Vol 198 ◽  
pp. 00003 ◽  
Author(s):  
P. Strasser ◽  
M. Abe ◽  
M. Aoki ◽  
S. Choi ◽  
Y. Fukao ◽  
...  
Keyword(s):  
Hyperfine Structure ◽  
Quantum Electrodynamics ◽  
Field Measurements ◽  
Bound State ◽  
New Physics ◽  
Muon Beam ◽  
Current Status ◽  
Zero Field ◽  
Order Of Magnitude ◽  
Muon Magnetic Moment

High precision measurements of the ground state hyperfine structure (HFS) of muonium is a stringent tool for testing bound-state quantum electrodynamics (QED) theory, determining fundamental constants of the muon magnetic moment and mass, and searches for new physics. Muonium is the most suitable system to test QED because both theoretical and experimental values can be precisely determined. Previous measurements were performed decades ago at LAMPF with uncertainties mostly dominated by statistical errors. At the J-PARC Muon Science Facility (MUSE), the MuSEUM collaboration is planning complementary measurements of muonium HFS both at zero and high magnetic field. The new high-intensity muon beam that will soon be available at H-Line will provide an opportunity to improve the precision of these measurements by one order of magnitude. An overview of the different aspects of these new muonium HFS measurements, the current status of the preparation for high-field measurements, and the latest results at zero field are presented.

New Experiment for the First Direct Measurement of Positronium Hyperfine Splitting with Sub-THz Light

2010 ◽  
Vol 666 ◽  
pp. 133-137 ◽  
Author(s):  
Akira Miyazaki ◽  
Takayuki Yamazaki ◽  
Taikan Suehara ◽  
Toshio Namba ◽  
Shoji Asai ◽  
...  
Keyword(s):  
Present Status ◽  
Quantum Electrodynamics ◽  
Hyperfine Splitting ◽  
Radiation Power ◽  
Bound State ◽  
New Physics ◽  
Ideal System ◽  
Fabry Perot ◽  
Current Design ◽  
High Finesse

Positronium is an ideal system for the research of Quantum Electrodynamics (QED), especially for QED in bound state. The discrepancy of 3.9σ was found recently between the measured HFS values and the QED prediction of O(α3). It might be due to the contribution of unknown new physics or systematic problems in the all previous measurements. We propose a new method to measure HFS directly and precisely. A gyrotron, a novel sub-THz light source is adopted with a Fabry-Pérot cavity with high finesse and an efficient transportation system in order to obtain sufficient radiation power at 203 GHz. The present status of the optimization studies and the current design of the experiment are described.

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