We are doing laser spectroscopy of the 2S-2P energy difference (Lamb shift) in muonic hydrogen, muonic deuterium and muonic helium-3 and -4 ions. The physics motivation includes
- measurement of the charge radii of the lightest nuclei (proton, deuteron, helium-3 and -4 nuclei)
- improved determination of the Rydberg constant
- test of bound-state quantum electrodynamics (QED)
- Zemach radius (magnetization) of the proton
- nuclear polarizabilities and test of few-nucleon models
Our Proposal on muonic helium gives you all the details.