Halo independent comparison of direct dark matter detection data

We extend the halo-independent method of Fox, Liu, and Weiner to include energy resolution and efficiency with arbitrary energy dependence, making it more suitable for experiments to use in pre-senting their results. Then we compare measurements and upper limits on the direct detection of low mass (~10 GeV) weakly interacting massive particles (WIMPs) with spin-independent interactions, including the preliminary upper limit on the annual modulation amplitude from the CDMS collab-oration. We find that isospin-symmetric couplings are severely constrained, but isospin-violating couplings are still possible if for example the local Galactic escape speed is small, as found in recent surveys.