Does the proton-to-electron mass ratio vary in the course of cosmological evolution?

Abstract

The possible cosmological variation of the proton-to-electron mass ratio was estimated by measuring the H_2 wavelengths in the high-resolution spectrum of the quasar Q~0347-382. Our analysis yielded an estimate for the possible deviation of μvalue in the past, 10 Gyr ago: for the unweighted value $\hat{I}”\hat{I}¼/\hat{I}¼=(3.0\pm 2.4)\times 10^{-5}$; for the weighted value \[ Δμ/ μ= (5.02\pm1.82)\times10^{-5}\] Since the significance of the both results does not exceed 3$\ddot{I}ƒ$, further observations are needed to increase the statistical significance. In any case, this result may be considered as the most stringent estimate on an upper limit of a possible variation of μ(95% C.L.): \[ |Δμ/ μ| < 8\times 10^{-5} \] This value serves as an effective tool for selection of models determining a relation between possible cosmological deviations of the fine-structure constant αand the elementary particle masses (m${}_p$, m${}_e$, etc.).

6 pages, 1 figure. Talk presented at the JENAM 2002 Workshop on Varying Fundamental Constants, Porto, 4th September 2002. To be published in the Conference Proceedings