Theory of the Lamb shift in muonic hydrogen

Muonic hydrogen (μH) is a unique tool to study the low-energy properties of the proton form factors. The energy levels of μH are very sensitive to QED, recoil, and proton finite-size effects. We calculate the corrections to the Lamb shift and also to the fine and hyperfine structures that contribute at the 0.01-meV precision level. This result may allow for the precise determination of the proton charge radius from measurements of the 2P-2S transition energy in μH. A more accurate value for the proton radius is necessary for further improvements of QED tests based on the hydrogen atom. © 1996 The American Physical Society.