The Proton Radius Puzzle

Feb 18, 2015
19 pages
Published in:
  • Prog.Part.Nucl.Phys. 82 (2015) 59-77
  • Published: May, 2015
e-Print:

Citations per year

201520182021202420250102030
Abstract: (Elsevier)
The proton size, specifically its charge radius, was thought known to about 1% accuracy. Now a new method probing the proton with muons instead of electrons finds a radius about 4% smaller, and to boot gives an uncertainty limit of about 0.1%. We review the different measurements, some of the calculations that underlie them, some of the suggestions that have been made to resolve the conflict, and give a brief overview new related experimental initiatives. At present, however, the resolution to the problem remains unknown.
Note:
  • Accepted invited review for Progress in Particle and Nuclear Physics. 28 pages, 15 figures
  • Proton radius
  • Form factors
  • Muonic atoms
  • p: size
  • p: charge radius
  • correction: Coulomb
  • correction: two-photon
  • hydrogen: muonic atom
  • deuterium: muonic atom