Test of CPT and Lorentz invariance from muonium spectroscopy

Abstract

Following a suggestion of Kostelecky et al. we have evaluated a test of CPT and Lorentz invariance from the microwave spectroscopy of muonium. Hamiltonian terms beyond the standard model violating CPT and Lorentz invariance would contribute frequency shifts $δν_{12}$ and $δν_{34}$ to $ν_{12}$ and $ν_{34}$, the two transitions involving muon spin flip, which were precisely measured in ground state muonium in a strong magnetic field of 1.7 T. The shifts would be indicated by anti-correlated oscillations in $ν_{12}$ and $ν_{34}$ at the earth's sidereal frequency. No time dependence was found in $ν_{12}$ or $ν_{34}$ at the level of 20 Hz, limiting the size of some CPT and Lorentz violating parameters at the level of $2\times10^{-23}$ GeV, representing Planck scale sensitivity and an order of magnitude improvement in sensitivity over previous limits for the muon.

4 pages, 4 figures, uses REVTeX and epsf, submitted to Phys. Rev. Lett