CMB constraints on the simultaneous variation of the fine structure constant and the electron mass

The University of Tokyo, Tōkyō, Japan
Physical Review D (Impact Factor: 4.86). 07/2006; 74(2). DOI: 10.1103/PhysRevD.74.023515
Source: arXiv

ABSTRACT We study constraints on time variation of the fine structure constant α from cosmic microwave background (CMB) taking into account simultaneous change in α and the electron mass me which might be implied in unification theories. We obtain the constraints -0.097<Δα/α<0.034 at 95% C.L. using WMAP data only, and -0.042<Δα/α<0.026 combining with the constraint on the Hubble parameter by the HST Hubble Key Project. These are improved by 15% compared with constraints assuming only α varies. We discuss other relations between variations in α and me but we do not find evidence for varying α.

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    ABSTRACT: We investigate constraints on the time variation of the fine structure constant between the recombination epoch and the present epoch from cosmic microwave background (CMB) in the case other physical constants, namely the electron mass m(e) and the proton mass m(p), varies simultaneously. Assuming a relation among the variations of coupling constants which is governed by a single scalar field called the dilaton, the constraint on Delta alpha/alpha is found to be -8.28 x 10(-3) < Delta alpha/alpha < 1.81 x 10(-3) at 95% confidence level (C.L.) where Delta alpha/alpha is defined as Delta alpha/alpha (alpha(rec) - alpha(0))/alpha(0). This result is tighter than the one obtained by considering only the change of alpha and m(e).
    06/2010; DOI:10.1063/1.3462643
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    ABSTRACT: We studied the role of fundamental constants in an updated recombination scenario, focusing on the time variation of the fine structure constant α and the electron mass m_e in the early Universe. Using CMB data including WMAP 5-yr release, and the 2dFGRS power spectrum, we put bounds on variations of these constants, when both constants are allowed to vary, and in the case that only one of them is variable. In particular, we have found that -0.019 < Δ α / α_0 < 0.017 (95% c.l.), in our joint estimation of α and cosmological parameters. Finally, we analyze how the constraints depends on the recombination scenario.
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