The proton radius puzzle is an unanswered problem in physics relating to the size of the proton. [1] Historically the proton charge radius was measured by two independent methods, which converged to a value of about 0.877 femtometres (1 fm = 10 −15 m).

The proton is a "bare charge" with only about 1/64,000 of the radius of a hydrogen atom, and so is extremely reactive chemically. The free proton, thus, has an extremely short lifetime in chemical systems such as liquids and it reacts immediately with the …

Jan 11, 2018 · Why atomic physics to learn proton radius? Why μH? Lepton mass to the third power! factor of about 8 million! The 2 keV X-rays from 2P to 1S are detected. Huh? “Most measurements of the radius of the proton involve electron-proton interactions, and most of the more recent values agree with one another...

Feb 1, 2014 · Today researchers trigger torrents of ultrahigh-energy proton collisions to conjure particle exotica such as the Higgs boson. Yet recent studies of the proton have surprised us.

Sep 30, 2020 · In this Review, we discuss the experimental techniques used to measure the proton radius and describe the current status of the field as well as forthcoming experiments.

Mar 16, 2023 · Using two types of ultraprecise measurement that each probed the proton’s electric charge, researchers pegged the particle’s radius as about 0.877 femtometer (a femtometer is a trillionth of...

Nov 11, 2019 · The result, published in Nature on 6 November, puts the particle’s radius at 0.831 femtometres. This measurement, together with a concurring one made using a different technique that was...

Oct 6, 2017 · The radius of the proton is very small, about 1 fm (1 fm is 10 −15 m), smaller than the radius of a hydrogen atom by a factor of 60,000. As a proton is such a fundamental particle, much effort is devoted to measuring its size.

Nov 6, 2019 · Atomic physicists determine the proton radius by measuring the energy difference between two electronic states of a hydrogen atom using spectroscopy. According to quantum mechanics, there is a...

The study of the proton charge radius (r p) has been historically instrumental towards the understanding of the nucleon structure. The disagreement of the r p as determined using different methods of extraction, namely through the measurement of the Lamb shift in the muonic hydrogen atom, startled the physics world and gave rise to the proton ...