e+e−peaks at 1.8 MeV: Phenomenological constraints on nuclear transitions, axions, and the particle interpretation

1986 ◽  
Vol 34 (11) ◽  
pp. 3385-3393 ◽  
Author(s):  
Lawrence M. Krauss ◽  
Michael Zeller
Keyword(s):  
Nuclear Transitions ◽  
Particle Interpretation

Vacuum polarization and particle creation in the presence of a potential step

2016 ◽  
Vol 31 (02n03) ◽  
pp. 1641031 ◽  
Author(s):  
S. P. Gavrilov ◽  
D. M. Gitman
Keyword(s):  
Electric Potential ◽  
Canonical Quantization ◽  
Particle Creation ◽  
Pair Creation ◽  
Dirac Field ◽  
Potential Step ◽  
Electron Positron ◽  
Physical Impact ◽  
Particle Interpretation ◽  
Electron Positron Pair

We consider QED with strong external backgrounds that are concentrated in restricted space areas. The latter backgrounds represent a kind of spatial x-electric potential steps for charged particles. They can create particles from the vacuum, the Klein paradox being closely related to this process. We describe a canonical quantization of the Dirac field with x-electric potential step in terms of adequate in- and out-creation and annihilation operators that allow one to have consistent particle interpretation of the physical system under consideration and develop a nonperturbative (in the external field) technics to calculate scattering, reflection, and electron-positron pair creation. We resume the physical impact of this development.

Possibility of using low-energy nuclear transitions as benchmarks for frequency stabilization

2007 ◽  
Vol 50 (12) ◽  
pp. 1231-1233 ◽  
Author(s):  
V. S. Aleksandrov ◽  
Yu. G. Zakharenko ◽  
N. A. Kononova ◽  
N. A. Mel’nikov ◽  
A. A. Pasternak ◽  
...  
Keyword(s):  
Frequency Stabilization ◽  
Low Energy ◽  
Nuclear Transitions

Engineering the sensitivity of macroscopic physical systems to variations in the fine-structure constant

2021 ◽  
Author(s):  
Beata Zjawin ◽  
Marcin Bober ◽  
Roman Ciuryło ◽  
Daniel Lisak ◽  
Michał Zawada ◽  
...  
Keyword(s):  
Fine Structure ◽  
Optical Cavity ◽  
Structure Constant ◽  
Relativistic Effects ◽  
Fine Structure Constant ◽  
Sensitivity Factor ◽  
Optical Cavities ◽  
Physical Systems ◽  
Heavy Atoms ◽  
Nuclear Transitions

Abstract Experiments aimed at searching for variations in the fine-structure constant α are based on spectroscopy of transitions in microscopic bound systems, such as atoms and ions, or resonances in optical cavities. The sensitivities of these systems to variations in α are typically on the order of unity and are fixed for a given system. For heavy atoms, highly charged ions and nuclear transitions, the sensitivity can be increased by benefiting from the relativistic effects and favorable arrangement of quantum states. This article proposes a new method for controlling the sensitivity factor of macroscopic physical systems. Specific concepts of optical cavities with tunable sensitivity to α are described. These systems show qualitatively different properties from those of previous studies of the sensitivity of macroscopic systems to variations in α, in which the sensitivity was found to be fixed and fundamentally limited to an order of unity. Although possible experimental constraints attainable with the specific optical cavity arrangements proposed in this article do not yet exceed the present best constraints on α variations, this work paves the way for developing new approaches to searching for variations in the fundamental constants of physics.

Neutron and proton components of nuclear transitions in pion inelastic scattering on 26Mg

1980 ◽  
Vol 97 (1) ◽  
pp. 37-40 ◽  
Author(s):  
C.-A. Wiedner ◽  
K.R. Cordell ◽  
W. Saathoff ◽  
S.T. Thornton ◽  
J. Bolger ◽  
...  
Keyword(s):  
Inelastic Scattering ◽  
Pion Inelastic Scattering ◽  
Nuclear Transitions

Nuclear Transitions and Radioactive Decay

2004 ◽  
pp. 31-42
Author(s):  
Subramania Jayaraman ◽  
Lawrence H. Lanzl
Keyword(s):  
Radioactive Decay ◽  
Nuclear Transitions

Nuclear Transitions in Muonic Molecules

1994 ◽  
pp. 201-203
Author(s):  
V. B. Belyaev ◽  
H. Fiedeldey ◽  
S. A. Rakityansky ◽  
S. A. Sofianos
Keyword(s):  
Nuclear Transitions
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