High-resolution laser spectroscopy is an established powerful tool in the study of nuclear
shape, size and multipole moments. Measurements of the hyperfine structures and isotope …

The extremely precise extraction of the proton radius obtained by Pohl et al. from the
measured energy difference between the 2 P and 2 S states of muonic hydrogen disagrees …

The 7σ discrepancy between the proton rms charge radius from muonic hydrogen and the
CODATA-2010 value from hydrogen spectroscopy and electron-scattering has caused …

We critically examine the current status of theoretical calculations of the energies, the fine
structure, and the isotope shift of the lowest-lying states of helium, searching for unresolved …

The neutron-rich He 6 and He 8 isotopes exhibit an exotic nuclear structure that consists of a
tightly bound He 4-like core with additional neutrons orbiting at a relatively large distance …

The 2 S 3–2 P 3 transition of He 4 was measured by comb-linked laser spectroscopy using a
transverse-cooled atomic beam. The centroid frequency was determined to be 276 736 495 …

The very high precision of current measurements and theory predictions of spectral lines in
few-electron atoms allows us to efficiently probe the existence of exotic forces between …

The prospects are explored for testing Lorentz and CPT symmetry in the muon sector via the
spectroscopy of muonium and various muonic atoms, and via measurements of the …

We measure the absolute frequency of seven out of the nine allowed transitions between the
2 S 3 and 2 P 3 hyperfine manifolds in a metastable He 3 beam by using an optical …

We give a pedagogical description of the method to extract the charge radii and Rydberg
constant from laser spectroscopy in regular hydrogen (H) and deuterium (D) atoms, that is …