Geometric dependence of the lensing signal, plotted vs. the distance ratio x ≡ ω _S /ω _L , for a WMAP7 cosmology with Ω _M = 0.27, . The solid (red) curve shows the theoretical prediction Γ( x) = 0 for x < 1; Γ( x) = 1 − 1/ x for x > 1. Note that the data have not been weighted for cosmological sensitivity (as in Section 4.2); a fit to the unweighted data favors a slightly shorter length scale for x (i.e., lower value of ) but with very large uncertainties.