The proton radius puzzle questions the self-consistency of theory and experiment in light muonic and electronic bound systems. Here we summarize the current status of virtual particle models as well as Lorentz-violating models that have been proposed in order to explain the discrepancy. Highly charged one-electron ions and muonic bound systems have been used as probes of the strongest electromagnetic fields achievable in the laboratory. The average electric field seen by a muon orbiting a proton is comparable to hydrogenlike uranium and, notably, larger than the electric field in the most advanced strong-laser facilities. Effective interactions due to virtual annihilation inside the proton (lepton pairs) and process-dependent corrections (nonresonant effects) are discussed as possible explanations of the proton size puzzle. The need for more experimental data on related transitions is emphasized.
U. D. Jentschura, "Muonic Bound Systems, Virtual Particles, and Proton Radius," Physical Review A - Atomic, Molecular, and Optical Physics, vol. 92, no. 1, pp. 012123-1-012123-10, American Physical Society (APS), Jul 2015.
The definitive version is available at https://doi.org/10.1103/PhysRevA.92.012123
Keywords and Phrases
Atomic Physics; Cesium; Cooling; Frequencies; Ground State; Hydrogen; Light Absorption; Magnetic Moments; Photodiodes; Rubidium; Ultrahigh Vacuum; Ultraviolet Radiation; Einstein's Equivalence Principle (EEP); Hyperfine Transitions; Radio Frequencies (RF); Transition Frequencies; Quantum Theory
International Standard Serial Number (ISSN)
Article - Journal
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01 Jul 2015