Abstract
Transition wavelengths on a large set of Lyman and Werner band spectral lines have been obtained at an accuracy of , using a narrow band tunable extreme ultraviolet laser. The data are used to determine a constraint on a possible cosmological variation of the proton-to-electron mass ratio () from a comparison with highly redshifted spectral data of quasistellar objects, yielding a fractional change in the mass ratio of (), which would correspond to a temporal change of per year () if a linear cosmological expansion model is assumed.
- Received 22 September 2003
DOI:https://doi.org/10.1103/PhysRevLett.92.101302
©2004 American Physical Society