Proton Structure from the Measurement of 2S-2P Transition Frequencies of Muonic Hydrogen

Antognini, Aldo; Nez, F.; Schuhmann, Karsten; Amaro, F. D.; Biraben, F.; Cardoso, J. M. R.; Covita, D. S.; Dax, A.; Dhawan, S.; Diepold, Marc; Fernandes, L. M. P.; Giesen, Adolf; Gouvea, Andrea L.; Graf, Thomas; Hänsch, Theodor W.; Indelicato, P.; Julién, L.; Kao, Cheng-Yang; Knowles, P.; Kottmann, F.; Bigot, Éric-Olivier Le; Liu, Yi-Wei; Lopes, J. A. M.; Ludhová, L.; Monteiro, C. M. B.; Mulhauser, F.; Nebel, Tobias; Rabinowitz, P.; Santos, J.M.F. dos; Schaller, L. A.; Schwob, Catherine; Taqqu, D.; Veloso, J.F.C.A.; Vogelsang, Jan; Pohl, Randolf

doi:10.1126/science.1230016

Cited by 802 publications

(994 citation statements)

References 46 publications

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“…which, however is in good agreement with the total result [28] used for the determination of the proton radius in [2]. This result is a pure prediction of the EFT, and it is also the most precise result that can be obtained in a model independent way since O(m µ α 5 m 3 µ Λ QCD ) effects are not controlled by the chiral theory and would require new counterterms.…”

Section: Lamb Shift and Extraction Of The Proton Radiussupporting

confidence: 84%

“…The recent measurement of the muonic hydrogen (µp) Lamb shift, E(2P 3/2 ) − E(2S 1/2 ) [1,2], ∆E exp L = 202.3706(23) meV (1) and the associated determination of the electromagnetic proton radius: r p = 0.84087(39) fm has led to a lot of controversy. The reason is that this number is 4-7σ away from previous determinations of this quantity coming from hydrogen and electron-proton (ep) scattering [3,4].…”

Section: Introductionmentioning

confidence: 99%

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The muonic hydrogen Lamb shift and the proton radius

Peset

2015

Nuclear and Particle Physics Proceedings

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We obtain a model independent expression for the muonic hydrogen Lamb shift up to O(m µ α 6 , m µ α 5 m 2 µ m 2 ρ ). The hadronic effects are controlled by the chiral theory, which allows for their model independent determination. We give their complete expression including the pion and Delta particles. Out of this analysis and the experimental measurement of the muonic hydrogen Lamb shift we determine the electromagnetic proton radius: r p =0.8412(15) fm. This number is at 6.8σ variance with respect to the CODATA value. The parametric control of the uncertainties allows us to obtain a model independent determination of the error, which is dominated by hadronic effects.

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Section: Lamb Shift and Extraction Of The Proton Radiussupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

The muonic hydrogen Lamb shift and the proton radius

Peset

2015

Nuclear and Particle Physics Proceedings

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show abstract

“…That is, all ingredients of the current matrix element in Fig. 4.3 [9] or using the muonic hydrogen value for the electric proton radius [578]. Figures adapted from Ref.…”

Section: Dyson-schwinger Calculationsmentioning

confidence: 99%

“…Phenomenologically speaking, a muon orbits closer to the proton than an electron and its energy levels are more strongly affected by the proton size. The CREMA collaboration has performed precision measurements of the 2P -2S transitions in muonic hydrogen [578,676]. The experimental result for the Lamb shift is E exp = 202.3706(23) meV, which has to be compared to the theoretical value [672] E th = 206.0336(15) − 5.2275(10) (R E /fm) 2 + E TPE .…”

Section: Overview Of Two-photon Physicsmentioning

confidence: 99%

Baryons as relativistic three-quark bound states

Eichmann

Sanchis-Alepuz

Williams

et al. 2016

Progress in Particle and Nuclear Physics

406

530

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We review the spectrum and electromagnetic properties of baryons described as relativistic three-quark bound states within QCD. The composite nature of baryons results in a rich excitation spectrum, whilst leading to highly non-trivial structural properties explored by the coupling to external (electromagnetic and other) currents. Both present many unsolved problems despite decades of experimental and theoretical research. We discuss the progress in these fields from a theoretical perspective, focusing on nonperturbative QCD as encoded in the functional approach via Dyson-Schwinger and Bethe-Salpeter equations. We give a systematic overview as to how results are obtained in this framework and explain technical connections to lattice QCD. We also discuss the mutual relations to the quark model, which still serves as a reference to distinguish 'expected' from 'unexpected' physics. We confront recent results on the spectrum of non-strange and strange baryons, their form factors and the issues of two-photon processes and Compton scattering determined in the DysonSchwinger framework with those of lattice QCD and the available experimental data. The general aim is to identify the underlying physical mechanisms behind the plethora of observable phenomena in terms of the underlying quark and gluon degrees of freedom.

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“…The measurement reported by the CREMA collaboration in [4] has found r p E = 0.84184 (67) fm, and more recently [5] r p E = 0.84087 (39) fm. Both of these muonic hydrogen extractions are in conflict with the CODATA 2010 [6] value r p E = 0.87580(770) fm, based on only hydrogen and deuterium spectroscopic data.…”

Section: Introductionmentioning

confidence: 99%

Model independent extraction of the proton magnetic radius from electron scattering

2014

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We combine constraints from analyticity with experimental electron-proton scattering data to determine the proton magnetic radius without model-dependent assumptions on the shape of the form factor. We also study the impact of including electron-neutron scattering data, and ππ → NN data. Using representative datasets we find for a cut of Q 2 ≤ 0.5 GeV 2 , r p M = 0.91 +0.03 −0.06 ± 0.02 fm using just proton scattering data; r p M = 0.87 +0.04 −0.05 ± 0.01 fm adding neutron data; and r p M = 0.87 +0.02 −0.02 fm adding ππ data. We also extract the neutron magnetic radius from these data sets obtaining r n M = 0.89 +0.03 −0.03 fm from the combined proton, neutron, and ππ data.

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Proton Structure from the Measurement of 2S-2P Transition Frequencies of Muonic Hydrogen

Cited by 802 publications

References 46 publications

The muonic hydrogen Lamb shift and the proton radius

The muonic hydrogen Lamb shift and the proton radius

Baryons as relativistic three-quark bound states

Model independent extraction of the proton magnetic radius from electron scattering

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