paper

Robust Constraint on a Drifting Proton-to-Electron Mass Ratio at z=0.89 from Methanol Observation at Three Radio Telescopes

arXiv:1311.3438 · doi:10.1103/PhysRevLett.111.231101

Abstract

A limit on a possible cosmological variation of the proton-to-electron mass ratio is derived from methanol (CHOH) absorption lines in the benchmark PKS1830211 lensing galaxy at redshift observed with the Effelsberg 100-m radio telescope, the Institute de Radio Astronomie Millimétrique 30-m telescope, and the Atacama Large Millimeter/submillimeter Array. Ten different absorption lines of CHOH covering a wide range of sensitivity coefficients are used to derive a purely statistical 1- constraint of for a lookback time of 7.5 billion years. Systematic effects of chemical segregation, excitation temperature, frequency dependence and time variability of the background source are quantified. A multi-dimensional linear regression analysis leads to a robust constraint of .

5 pages, 3 figures. Published in PRL

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