DISCLAIMER: This article is being kept online for historical purposes. Though accurate at last review, it is no longer being updated. The page may contain broken links or outdated information.
Proton radius from muonic hydrogen
Pohl, Randolf Laser Spectroscopy Division, Max Planck Institute of Quantum Optics, Garching, Germany.
- Proton charge radius
- Elastic electron-proton scattering
- Hydrogen spectroscopy
- Muonic hydrogen spectroscopy
- Proton radius puzzle
- Physics beyond the Standard Model
- Related Primary Literature
- Additional Reading
The recent measurement of the Lamb shift (2S-2P energy difference) in muonic hydrogen (μp) resulted in a new determination of the root-mean-square (rms) charge radius of the proton, rp = 0.8418 ± 0.0007 femtometer (1 fm = 10−15 m), which is 10 times more accurate than any previous determination from elastic electron-proton (e-p) scattering or precision spectroscopy of energy levels in the hydrogen atom (H), but differs by seven standard deviations from these measurements (Fig. 1). This discrepancy is now known as the “proton radius puzzle.” This article reviews the traditional methods for the determination of rp, describes the muonic hydrogen experiment, and reviews the attempts to resolve the puzzle, including suggestions for physics beyond the standard model.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information