## Constraining the time variation of the coupling constants from cosmic microwave background: effect of Λ{sub QCD}

We investigate constraints on the time variation of the fine structure constant between the recombination epoch and the present epoch, Δα/α≡(α{sub rec}−α{sub now})/α{sub now}, from cosmic microwave background (CMB) taking into account simultaneous variation of other physical constants, namely the electron mass m{sub e} and the proton mass m{sub p}. In other words, we consider the variation of Yukawa coupling and the QCD scale Λ{sub QCD} in addition to the electromagnetic coupling. We clarify which parameters can be determined from CMB temperature anisotropy in terms of singular value decomposition. Assuming a relation among variations of coupling constants governed by amore »