Abstract
We report a refined determination of muonium 1S-2S transition frequency and its isotope shift with deuterium by recalibrating the iodine reference lines using an optical frequency comb. The reference lines for the muonium and deuterium 1S-2S transitions are determined with a precision of 2.4×10-10 and 1.7×10-10, respectively. An updated muonium-deuterium 1S-2S isotope-shift frequency is derived from these references to be 11 203 464.9(9.2)(4.0) MHz, in agreement with an updated bound-state quantum-electrodynamics prediction based on 2010 adjustments of Committee on Data for Science and Technology and 2.3 times better in the systematic uncertainty than V. Meyer et al. [Phys. Rev. Lett. 84, 1136 (2000)PRLTAO0031- 900710.1103/PhysRevLett.84.1136]. © 2014 American Physical Society.