scholarly journals The Rydberg constant and proton size from atomic hydrogen

Science ◽  
2017 ◽  
Vol 358 (6359) ◽  
pp. 79-85 ◽  
Author(s):  
Axel Beyer ◽  
Lothar Maisenbacher ◽  
Arthur Matveev ◽  
Randolf Pohl ◽  
Ksenia Khabarova ◽  
...  
Keyword(s):  
Atomic Hydrogen ◽  
Quantum Interference ◽  
Muonic Hydrogen ◽  
Mean Square ◽  
Charge Radii ◽  
The Core ◽  
Proton Radius ◽  
Rydberg Constant ◽  
Proton Radius Puzzle ◽  
Good Agreement

At the core of the “proton radius puzzle” is a four–standard deviation discrepancy between the proton root-mean-square charge radii (rp) determined from the regular hydrogen (H) and the muonic hydrogen (µp) atoms. Using a cryogenic beam of H atoms, we measured the 2S-4P transition frequency in H, yielding the values of the Rydberg constantR∞= 10973731.568076(96) per meterandrp= 0.8335(95) femtometer. Ourrpvalue is 3.3 combined standard deviations smaller than the previous H world data, but in good agreement with the µp value. We motivate an asymmetric fit function, which eliminates line shifts from quantum interference of neighboring atomic resonances.

scholarly journals Two-photon frequency comb spectroscopy of atomic hydrogen

Science ◽  
2020 ◽  
Vol 370 (6520) ◽  
pp. 1061-1066 ◽  
Author(s):  
Alexey Grinin ◽  
Arthur Matveev ◽  
Dylan C. Yost ◽  
Lothar Maisenbacher ◽  
Vitaly Wirthl ◽  
...  
Keyword(s):  
Quantum Electrodynamics ◽  
Atomic Hydrogen ◽  
Frequency Comb ◽  
Muonic Hydrogen ◽  
Significant Discrepancy ◽  
Two Photon ◽  
Proton Radius ◽  
Proton Charge ◽  
Proton Charge Radius ◽  
Proton Radius Puzzle

We have performed two-photon ultraviolet direct frequency comb spectroscopy on the 1S-3S transition in atomic hydrogen to illuminate the so-called proton radius puzzle and to demonstrate the potential of this method. The proton radius puzzle is a significant discrepancy between data obtained with muonic hydrogen and regular atomic hydrogen that could not be explained within the framework of quantum electrodynamics. By combining our result [f1S-3S = 2,922,743,278,665.79(72) kilohertz] with a previous measurement of the 1S-2S transition frequency, we obtained new values for the Rydberg constant [R∞ = 10,973,731.568226(38) per meter] and the proton charge radius [rp = 0.8482(38) femtometers]. This result favors the muonic value over the world-average data as presented by the most recent published CODATA 2014 adjustment.

scholarly journals Is the proton radius a player in the redefinition of the International System of Units?

2011 ◽  
Vol 369 (1953) ◽  
pp. 4064-4077 ◽  
Author(s):  
F. Nez ◽  
A. Antognini ◽  
F. D. Amaro ◽  
F. Biraben ◽  
J. M. R. Cardoso ◽  
...  
Keyword(s):  
International System ◽  
Muonic Hydrogen ◽  
Fundamental Constants ◽  
Relative Uncertainty ◽  
Proton Radius ◽  
System Of Units ◽  
Rydberg Constant ◽  
Proton Radius Puzzle ◽  
Electron Magnetic Moment ◽  
Theory And Experiment

It is now recognized that the International System of Units (SI units) will be redefined in terms of fundamental constants, even if the date when this will occur is still under debate. Actually, the best estimate of fundamental constant values is given by a least-squares adjustment, carried out under the auspices of the Committee on Data for Science and Technology (CODATA) Task Group on Fundamental Constants. This adjustment provides a significant measure of the correctness and overall consistency of the basic theories and experimental methods of physics using the values of the constants obtained from widely differing experiments. The physical theories that underlie this adjustment are assumed to be valid, such as quantum electrodynamics (QED). Testing QED, one of the most precise theories is the aim of many accurate experiments. The calculations and the corresponding experiments can be carried out either on a boundless system, such as the electron magnetic moment anomaly, or on a bound system, such as atomic hydrogen. The value of fundamental constants can be deduced from the comparison of theory and experiment. For example, using QED calculations, the value of the fine structure constant given by the CODATA is mainly inferred from the measurement of the electron magnetic moment anomaly carried out by Gabrielse's group. (Hanneke et al. 2008 Phys. Rev. Lett. 100 , 120801) The value of the Rydberg constant is known from two-photon spectroscopy of hydrogen combined with accurate theoretical quantities. The Rydberg constant, determined by the comparison of theory and experiment using atomic hydrogen, is known with a relative uncertainty of 6.6×10 −12 . It is one of the most accurate fundamental constants to date. A careful analysis shows that knowledge of the electrical size of the proton is nowadays a limitation in this comparison. The aim of muonic hydrogen spectroscopy was to obtain an accurate value of the proton charge radius. However, the value deduced from this experiment contradicts other less accurate determinations. This problem is known as the proton radius puzzle. This new determination of the proton radius may affect the value of the Rydberg constant . This constant is related to many fundamental constants; in particular, links the two possible ways proposed for the redefinition of the kilogram, the Avogadro constant N A and the Planck constant h . However, the current relative uncertainty on the experimental determinations of N A or h is three orders of magnitude larger than the ‘possible’ shift of the Rydberg constant, which may be shown by the new value of the size of the proton radius determined from muonic hydrogen. The proton radius puzzle will not interfere in the redefinition of the kilogram. After a short introduction to the properties of the proton, we will describe the muonic hydrogen experiment. There is intense theoretical activity as a result of our observation. A brief summary of possible theoretical explanations at the date of writing of the paper will be given. The contribution of the proton radius puzzle to the redefinition of SI-based units will then be examined.

Illuminating the proton radius conundrum: the μHe+ Lamb shiftThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at École de Physique, les Houches, France, 30 May – 4 June, 2010.

2011 ◽  
Vol 89 (1) ◽  
pp. 47-57 ◽  
Author(s):  
A. Antognini ◽  
F. Biraben ◽  
J. M.R. Cardoso ◽  
D. S. Covita ◽  
A. Dax ◽  
...  
Keyword(s):  
Nuclear Polarization ◽  
Bound State ◽  
Atomic Systems ◽  
Charge Radii ◽  
Polarization Contribution ◽  
Proton Radius ◽  
Nuclear Rms Charge Radii ◽  
Proton Radius Puzzle ◽  
Bound State Qed

We plan to measure several 2S–2P transition frequencies in μ4He+ and μ3He+ by means of laser spectroscopy with an accuracy of 50 ppm. This will lead to a determination of the corresponding nuclear rms charge radii with a relative accuracy of 3 × 10−4, limited by the uncertainty of the nuclear polarization contribution. First, these measurements will help to solve the proton radius puzzle. Second, these very precise nuclear radii are benchmarks for ab initio few-nucleon theories and potentials. Finally when combined with an ongoing measurement of the 1S–2S transition in He+, these measurements will lead to an enhanced bound-state QED test of the 1S Lamb shift in He+.

Solution to the proton radius puzzle

2014 ◽  
Vol 23 (12) ◽  
pp. 1450090 ◽  
Author(s):  
D. Robson
Keyword(s):  
Form Factor ◽  
Electron Scattering ◽  
Charge Radius ◽  
Rest Frame ◽  
Muonic Hydrogen ◽  
Electric Form Factor ◽  
Scattering Data ◽  
Proton Radius ◽  
Proton Charge Radius ◽  
Proton Radius Puzzle

The relationship between the static electric form factor for the proton in the rest frame and the Sachs electric form factor in the Breit momentum frame is used to provide a value for the difference in the mean squared charge radius of the proton evaluated in the two frames. Associating the muonic–hydrogen data analysis for the proton charge radius of 0.84087 fm with the rest frame and associating the electron scattering data with the Breit frame yields a prediction of 0.87944 fm for the proton radius in the relativistic frame. The most recent value deduced via electron scattering from the proton is 0.877(6) fm so that the frame dependence used here yields a plausible solution to the proton radius puzzle.

scholarly journals The proton radius puzzle – 9 years later

2020 ◽  
Vol 234 ◽  
pp. 01001 ◽  
Author(s):  
Jan C. Bernauer
Keyword(s):  
High Precision ◽  
Nuclear Physics ◽  
Muonic Hydrogen ◽  
Precision Measurements ◽  
Proton Radius ◽  
Short Summary ◽  
Proton Radius Puzzle

High-precision measurements of the proton radius via scattering, electric hydrogen spectroscopy and muonic hydrogen spectroscopy do not agree on the level of more than 5 σ. This proton radius puzzle persists now for almost a decade. This paper gives a short summary over the progress in the solution of the puzzle as well as an overview over the planned experiments to finally solve this puzzle at the interface of atomic and nuclear physics.

A measurement of the atomic hydrogen Lamb shift and the proton charge radius

Science ◽  
2019 ◽  
Vol 365 (6457) ◽  
pp. 1007-1012 ◽  
Author(s):  
N. Bezginov ◽  
T. Valdez ◽  
M. Horbatsch ◽  
A. Marsman ◽  
A. C. Vutha ◽  
...  
Keyword(s):  
Direct Measurement ◽  
Charge Radius ◽  
Atomic Hydrogen ◽  
Lamb Shift ◽  
Shift Measurement ◽  
Proton Radius ◽  
Proton Charge ◽  
Proton Charge Radius ◽  
Proton Radius Puzzle

The surprising discrepancy between results from different methods for measuring the proton charge radius is referred to as the proton radius puzzle. In particular, measurements using electrons seem to lead to a different radius compared with those using muons. Here, a direct measurement of the n = 2 Lamb shift of atomic hydrogen is presented. Our measurement determines the proton radius to be rp = 0.833 femtometers, with an uncertainty of ±0.010 femtometers. This electron-based measurement of rp agrees with that obtained from the analogous muon-based Lamb shift measurement but is not consistent with the larger radius that was obtained from the averaging of previous electron-based measurements.

The Lamb shift in muonic hydrogen and the proton radius puzzle

2014 ◽  
Vol 227 (1-3) ◽  
pp. 23-28 ◽  
Author(s):  
Randolf Pohl ◽  
Keyword(s):  
Lamb Shift ◽  
Muonic Hydrogen ◽  
Proton Radius ◽  
Proton Radius Puzzle

scholarly journals Muonic hydrogen spectroscopy: the proton radius puzzle

2010 ◽  
Author(s):  
Aldo Antognini ◽  
François Nez ◽  
Fernando D. Amaro ◽  
François Biraben ◽  
João M. R. Cardoso ◽  
...  
Keyword(s):  
Muonic Hydrogen ◽  
Proton Radius ◽  
Proton Radius Puzzle

scholarly journals PROTON RADIUS PUZZLE AND LARGE EXTRA DIMENSIONS

2013 ◽  
Vol 28 (20) ◽  
pp. 1350094 ◽  
Author(s):  
LI-BANG WANG ◽  
WEI-TOU NI
Keyword(s):  
Modified Gravity ◽  
Electromagnetic Interaction ◽  
Large Extra Dimensions ◽  
Gravitational Interaction ◽  
Energy Shift ◽  
Muonic Hydrogen ◽  
New Physics ◽  
Proton Radius ◽  
Stringent Constraint ◽  
Proton Radius Puzzle

We propose a theoretical scenario to solve the proton radius puzzle which recently arises from the muonic hydrogen experiment. In this framework, (4+n)-dimensional theory is incorporated with modified gravity. The extra gravitational interaction between the proton and muon at very short range provides an energy shift which accounts for the discrepancy between spectroscopic results from muonic and electronic hydrogen experiments. Assuming the modified gravity is a small perturbation to the existing electromagnetic interaction, we find the puzzle can be solved with stringent constraint on the range of the new force. Our result not only provides a possible solution to the proton radius puzzle but also suggests a direction to test new physics at very small length scale.

scholarly journals Muonic Hydrogen and the Proton Radius Puzzle

2013 ◽  
Vol 63 (1) ◽  
pp. 175-204 ◽  
Author(s):  
Randolf Pohl ◽  
Ronald Gilman ◽  
Gerald A. Miller ◽  
Krzysztof Pachucki
Keyword(s):  
Muonic Hydrogen ◽  
Proton Radius ◽  
Proton Radius Puzzle
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