New Limits on the Drift of Fundamental Constants from Laboratory Measurements

We have remeasured the absolute 1S-2S transition frequency ₇ in atomic hydrogen. A comparison with the result of the previous measurement performed in 1999 sets a limit of (-2957) Hz for the drift of ₇ with respect to the ground state hyperfine splitting ₂ₒ in ^133Cs. Combining this result with the recently published optical transition frequency in ^199Hg^+ against ₂ₒ and a microwave ^87Rb and ^133Cs clock comparison, we deduce separate limits on /= (-0. 92. 9) 10^-15 yr^-1 and the fractional time variation of the ratio of Rb and Cs nuclear magnetic moments ₑ₁/₂ₒ equal to (-0. 51. 7) 10^-15 yr^-1. The latter provides information on the temporal behavior of the constant of strong interaction.