Precision Physics of Simple Atoms and Constraints on a Light Boson with Ultraweak Coupling

Constraint on spin-dependent and spin-independent Yukawa potential at atomic scale is developed. That covers constraints on a coupling constant of an additional photon γ* and a pseudovector boson. The mass range considered is from 1 eV/c² to 1 MeV/c². The strongest constraint on a coupling constant α^' is at the level of a few parts in 10¹³ (for γ*) and below one part in 10¹⁶ (for a pseudovector) corresponding to mass below 1 keV/c². The constraints are derived from low-energy tests of quantum electrodynamics and are based on spectroscopic data on light hydrogenlike atoms and experiments with magnetic moments of leptons and light nuclei.