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Centro de Astrofísica da Universidade do Porto

Measuring α in the Early Universe

G. Rocha

Abstract
We update the bounds on a time-varying fine structure constant alpha at the time of BBN (z~1010) and CMB (z~103) and present the current CMB constraints on α, through a combined analysis of the BOOMERanG, MAXIMA and DASI datasets. We also present a discussion of the constraints on α coming from large-scale structure observations, focusing in particular on the power spectrum from the 2dF survey. Finally we provide a analysis of the degeneracies between α and the other cosmological parameters and discuss ways to break these with both existing and/or forthcoming data. Our results are consistent with no variation in α from the epoch of recombination to the present day, and restrict any such variation to be less than about 4%. We show that the forthcoming MAP and Planck experiments will be able to break most of the currently existing degeneracies between α and other parameters, and measure α to better than percent accuracy.

Astrophysics and Space Science
Volume 283, Page 589
March 2003

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