TestingCPTand Lorentz symmetry with hydrogen masers

In a recent paper [Phys. Rev. D 63, 111101 (2001)] we reported a new limit on CPT (charge, parity, and time reversal) and Lorentz violation of the proton by using a hydrogen maser to search for a sidereal variation of the $F=1,$ ΔmF=±1 Zeeman frequency in atomic hydrogen. Here we discuss the theoretical interpretation of this recent experiment, the operating principles of the maser, and the double-resonance technique used to measure the Zeeman frequency. We also describe the characterization of systematic effects and details of the data analysis. We conclude by comparing our result to other recent experiments, and discussing potential improvements to the hydrogen maser double-resonance technique.