A small proton charge radius from an electron–proton scattering experiment

  title={A small proton charge radius from an electron–proton scattering experiment},
  author={Weizhi Xiong and A. Gasparian and H. Gao and D. Dutta and M. Khandaker and Nilanga K. Liyanage and Eugene Pasyuk and Chao Peng and Xinzhan Bai and Li Ye and Kondo Gnanvo and Chao Gu and Maxime Levillain and X. Yan and Douglas W. Higinbotham and Mehdi Meziane and Zhihong Ye and K. Adhikari and Bashar Aljawrneh and H. Bhatt and D. Bhetuwal and James Brock and Volker D. Burkert and C. Carlin and Alexandre Deur and Danning Di and James A. Dunne and P. Ekanayaka and Lamiaa El-Fassi and B. Emmich and Liping Gan and O. Glamazdin and Mohammad Lutful Kabir and A. Karki and Christopher Keith and Stanley B. Kowalski and Victoria Lagerquist and I. Larin and T. Liu and Anusha Liyanage and James D. Maxwell and D. Meekins and Sahara Jesmin Nazeer and Vladimir Nelyubin and Hung T. Nguyen and R. Pedroni and C. F. Perdrisat and J. Pierce and Vina Punjabi and Maryam Hashemi Shabestari and Albert Shahinyan and Rupesh Silwal and Stepan Stepanyan and Adesh Subedi and V. V. Tarasov and Nguyen Ton and Y. Zhang and Z. W. Zhao},
Elastic electron–proton scattering (e–p) and the spectroscopy of hydrogen atoms are the two methods traditionally used to determine the proton charge radius, r p. In 2010, a new method using muonic hydrogen atoms1 found a substantial discrepancy compared with previous results2, which became known as the ‘proton radius puzzle’. Despite experimental and theoretical efforts, the puzzle remains unresolved. In fact, there is a discrepancy between the two most recent spectroscopic measurements… 

The proton size

The proton charge radius has been measured since the 1950s using elastic electron–proton scattering and ordinary hydrogen atomic spectroscopy. In 2010, a highly precise measurement of the proton

Elastic positron–proton scattering at low Q$$^2$$

Systematic differences in the the proton’s charge radius, as determined by ordinary atoms and muonic atoms, have caused a resurgence of interest in elastic lepton scattering measurements. The

Transverse charge density and the radius of the proton

A puzzling discrepancy exists between the values of the proton charge radius obtained using different experimental techniques: elastic electron-proton scattering and spectroscopy of electronic and

The proton radius: from a puzzle to precision

A High Precision Measurement of the Proton Charge Radius at JLab

The elastic electron-proton ($e-p$) scattering and the spectroscopy of hydrogen atoms are the two traditional methods to determine the proton charge radius ($r_{p}$). In 2010, a new method using the

The proton charge radius

Nucleons (protons and neutrons) are the building blocks of atomic nuclei, and are responsible for more than 99% of the visible matter in the universe. Despite decades of efforts in studying its

Measuring the α-particle charge radius with muonic helium-4 ions

The measurement of two 2S–2P transitions in the muonic helium-4 ion yields a precise determination of the root-mean-square charge radius of the α particle, providing a benchmark for few-nucleon theories, lattice quantum chromodynamics and electron scattering.


A slight anomaly in optical spectra of the hydrogen atom led Willis E. Lamb to the search for the proton size. As a result, he found the shift of the 2S1/2 level, the first experimental demonstration

The proton radius (puzzle?) and its relatives

Proton-electron mass ratio from laser spectroscopy of HD+ at the part-per-trillion level

By leveraging high-precision ab initio calculations, the researchers converted their measurement to tight constraints on the proton-electron and deuteron-proton mass ratios, consistent with the most recent Penning trap determinations of these quantities.



Proton radius from electron scattering data

Background: The proton charge radius extracted from recent muonic hydrogen Lamb shift measurements is significantly smaller than that extracted from atomic hydrogen and electron scattering

The Rydberg constant and proton size from atomic hydrogen

The authors obtained the size of the proton using very accurate spectroscopic measurements of regular hydrogen using an asymmetric fit function, which eliminates line shifts from quantum interference of neighboring atomic resonances.

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

Accurate knowledge of the charge and Zemach radii of the proton is essential, not only for understanding its structure but also as input for tests of bound-state quantum electrodynamics and its predictions for the energy levels of hydrogen.

Extraction of the proton radius from electron-proton scattering data

We perform a new analysis of electron-proton scattering data to determine the proton electric and magnetic radii, enforcing model-independent constraints from form factor analyticity. A wideranging

The size of the proton

The root-mean-square charge radius, rp, has been determined with an accuracy of 2 per cent by electron–proton scattering experiments, and the present most accurate value of rp (with an uncertainty of 1 per cent) is given by the CODATA compilation of physical constants.

Are Electron Scattering Data Consistent with a Small Proton Radius?

We determine the charge radius of the proton by analyzing the published low momentum transfer electronproton scattering data from Mainz. We note that polynomial expansions of the form factor converge

Radiative corrections beyond the ultra relativistic limit in unpolarized ep elastic and Møller scatterings for the PRad Experiment at Jefferson Laboratory

The clear 7σ discrepancy between measurements of the proton charge radius from muonic hydrogen Lamb shifts and those from hydrogen Lamb shift and electron scattering lead to both intense theoretical

( A New Proposal to Jefferson Lab PAC-38 ) High Precision Measurement of the Proton Charge Radius

We propose to perform a high precision e − p elastic cross sections measurement at very low four-momentum transfer squared, Q, from 10−4 to 10−2 (GeV/c) range using a high resolution calorimeter. The

Robust extraction of the proton charge radius from electron-proton scattering data

Extracting the proton charge radius from electron scattering data requires determining the slope of the charge form factor at $Q^2$ of zero. But as experimental data never reach that limit, numerous