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It has been argued recently that the inclusion of the chiral logarithms in extrapolation of the lattice data can shift the value of the hadronic parameter ξ = fBs √ B̂Bs/fBd √ B̂Bd , from 1.16(6) to 1.32(10) and even higher. If true, that would considerably change the theoretical estimate for the ratio of oscillation frequencies in the B0 s and B 0 d-systems, and would affect the standard CKM unitarity triangle analysis. In this letter we show that fBs/fBd ≈ fK/fπ, and thus the uncertainty due to the missing chiral logs is smaller than previously thought. By combining the NLO chiral expansion with the static heavy quark limit we obtain ξ = 1.22(7). 1 Uncertainty in ∆mBs/∆mBd comes from fBs/fBd TheK0−K̄0 andB0−B̄0 mixing amplitudes are the main ingredients in the standard unitarity triangle analysis [1]. They overconstrain the apex of the CKM triangle in the (ρ̄, η̄)-plane. Confronting such an overconstrained triangle with the directly measured sin(2β) [2] allows for the consistency check from which we hope to either see the effects of the non-Standard Model physics, or simply to confirm the validity of Standard Model at the accessible accuracy [3]. One of the essential constraints is provided by the ratio of oscillation frequencies ∆mBd ∆mBs = ∣∣∣∣ Vtd Vts ∣∣∣∣ 2 mBd mBs 1 ξ2 ≃ λ [ (1− ρ̄) + η̄ ] mBd mBs 1 ξ2 +O(λ) , (1)