New precision measurements of the muonic X-ray transition in 24Mg and 28Si: Vacuum polarisation test and search for muon-hadron interactions beyond QED

Beltrami, I.; Aas, B.; Beer, W.; Chambrier, G. De; Goudsmit, P.F.A.; Ledebur, Th.v.; Leisi, H.J.; Ruckstuhl, W.; Sapp, W.W.; Strassner, G.; Vacchi, A.; Kiebele, U.; Pinston, J.A.; Weber, Roman

doi:10.1016/0375-9474(86)90299-x

Cited by 59 publications

(30 citation statements)

References 47 publications

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“…After a sign error in the calculation of the two-loop vacuum polarization correction [30] was eliminated [31,32] and a standard γ-ray spectrometer used in the experiments was recalibrated [33], other experiments later found agreement of theory and experiment in muonic systems (e.g., Refs. [34,35]). Nuclear radii of some carbon, nitrogen and oxygen isotopes [36] were determined by analyzing muonic transitions, and the resulting radii were found to be in agreement with electron scattering radii to better than 5 %.…”

Section: Discussionmentioning

confidence: 99%

Light sea fermions in electron-proton and muon-proton interactions

Jentschura

2013

Phys. Rev. A

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The proton radius conundrum [R. Pohl et al., Nature 466, 213 (2010) and A. Antognini et al. Science 339, 417 (2013)] highlights the need to revisit any conceivable sources of electron-muon nonuniversality in lepton-proton interactions within the Standard Model. Superficially, a number of perturbative processes could appear to lead to such a nonunversality. One of these is a coupling of the scattered electron into an electronic as opposed to a muonic vacuum polarization loop in the photon exchange of two valence quarks, which is present only for electron projectiles as opposed to muon projectiles. However, we can show that this effect actually is part of the radiative correction to the proton's polarizability contribution to the Lamb shift, equivalent to a radiative correction to double scattering. We conclude that any conceivable genuine nonuniversality must be connected with a nonperturbative feature of the proton's structure, e.g., with the possible presence of light sea fermions as constituent components of the proton. If we assume an average of roughly 0.7 × 10 −7 light sea positrons per valence quark, then we can show that virtual electron-positron annihiliation processes lead to an extra term in the electron-proton versus muon-proton interaction, which has the right sign and magnitude to explain the proton radius discrepancy.

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Section: Discussionmentioning

confidence: 99%

Light sea fermions in electron-proton and muon-proton interactions

Jentschura

2013

Phys. Rev. A

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“…Muonic bound systems have been used as probes of the strongest electromagnetic fields since the 1970s (see Ref. [5]), but progress was eventually hindered due to electron screening [42]. Typically, transitions in high-Z muonic ions involve highly excited, non-S states [43][44][45], where the average field experienced by the orbiting electron is reduced due to the higher principle quantum number.…”

Section: Strong-field Electrodynamicsmentioning

confidence: 99%

Muonic bound systems, virtual particles, and proton radius

Jentschura

2015

Phys. Rev. A

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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.

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“…The last entry here is the constraint imposed by the agreement of the measured 2p − 3d transition frequencies in muonic magnesium and silicon with the corresponding QED predictions [35].…”

Section: Combination Of All Constraintsmentioning

confidence: 99%

“…(11) and (15) respectively, while for the muonic Si and Mg we take the weighted mean of the results from Ref. [35] and allow for a 2σ deviation,…”

Section: Combination Of All Constraintsmentioning

confidence: 99%

Constraints on muon-specific dark forces

2014

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The recent measurement of the Lamb shift in muonic hydrogen allows for the most precise extraction of the charge radius of the proton which is currently in conflict with other determinations based on e − p scattering and hydrogen spectroscopy. This discrepancy could be the result of some new muon-specific force with O(1-100) MeV force carrier-in this paper we concentrate on vector mediators. Such an explanation faces challenges from the constraints imposed by the g − 2 of the muon and electron as well as precision spectroscopy of muonic atoms. In this work we complement the family of constraints by calculating the contribution of hypothetical forces to the muonium hyperfine structure. We also compute the two-loop contribution to the electron parity violating amplitude due to a muon loop, which is sensitive to the muon axial-vector coupling. Overall, we find that the combination of low-energy constraints favors the mass of the mediator to be below 10 MeV, and that a certain degree of tuning is required between vector and axial-vector couplings of new vector particles to muons in order to satisfy constraints from muon g − 2. However, we also observe that in the absence of a consistent standard model embedding, high energy weak-charged processes accompanied by the emission of new vector particles are strongly enhanced by (E/mV ) 2 , with E a characteristic energy scale and mV the mass of the mediator. In particular, leptonic W decays impose the strongest constraints on such models completely disfavoring the remainder of the parameter space.

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New precision measurements of the muonic X-ray transition in 24Mg and 28Si: Vacuum polarisation test and search for muon-hadron interactions beyond QED

Cited by 59 publications

References 47 publications

Light sea fermions in electron-proton and muon-proton interactions

Light sea fermions in electron-proton and muon-proton interactions

Muonic bound systems, virtual particles, and proton radius

Constraints on muon-specific dark forces

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