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CMB constraints on the fine structure constant

Kazuhide Ichikawa·Toru Kanzaki·Masahiro Kawasaki
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Abstract

We study constraints on time variation of the fine structure constant alpha from cosmic microwave background (CMB) taking into account simultaneous change in alpha and the electron mass m_e which might be implied in unification theories. We obtain the constraints -0.097 < Delta alpha/alpha < 0.034 at 95% C.L. using WMAP data only, and -0.042 < Delta alpha/alpha < 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 alpha varies. We discuss other relations between variations in alpha and m_e but we do not find evidence for varying alpha.

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Kazuhide Ichikawa, Toru Kanzaki, Masahiro Kawasaki. 2006-05-25. CMB constraints on the fine structure constant. https://doi.org/10.1103/physrevd.74.023515

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