Ammonia as a Tracer of Fundamental Constants
Abstract
Observing inversion lines of ammonia (NH3), complemented by rotational lines of NH3 and other molecular species, provides stringent constraints on potential variations of the proton-to-electron mass ratio. While a limit of one part per million is derived for a lookback time of 7 billion years, nearby dark clouds might show a statistically significant variation of order 20-30 parts per billion, possibly being related to chameleon fields. The detection of radio-loud quasars with strong molecular absorption lines at redshifts z > 1 as well as the identification of a larger sample of nearby dark clouds with exceptionally narrow lines (<0.2 km/s) would be essential to improve present limits and to put the acquired results onto a firmer statistical basis.
Keywords
Cite
@article{arxiv.1004.0912,
title = {Ammonia as a Tracer of Fundamental Constants},
author = {C. Henkel and K. M. Menten and M. T. Murphy and V. V. Flambaum and S. A. Levshakov and A. V. Lapinov and P. Molaro and J. A. Braatz},
journal= {arXiv preprint arXiv:1004.0912},
year = {2010}
}
Comments
3 pages, Contribution to the 12th Marcel Grossmann Meeting (MG12) in Paris, 2009 July 12-18,Parallel session EG2 (Variation of Fundamental Constants, Chair V. V. Flambaum)