Half-lives of Feshbach dimers prepared in the first and second Bloch bands of an optical lattice (orange circles and magenta squares, respectively). The lattice depth is V0(M) = 8 Erec(M) and θ = 0.4π for the first Bloch band and 0.535π for the second Bloch band. The black solid line is a common fit for data of both bands within the domain ξ > 2 with a straight line, extrapolated to the domain ξ < 2 (dashed continuation), indicating a power law τ ⊂ ξ − κ with κ = 1.28 ± 0.06. The error bars for τ = (n0β)−1 in a and b are determined by propagating the errors for n0 and β obtained in the fit procedure applied to determine τ. For data symbols with no visible error bar, the error is smaller than the symbol diameter. Each data point in a lifetime measurement averages over six experimental repetitions. The insets at the top boundary of b illustrate the different relaxation paths found in the second Bloch band for small and large ξ.
