Importance of upgraded energy reconstruction for direct dark matter searches with liquid xenon detectors

The usual nuclear recoil energy reconstruction employed by liquid xenon dark matter search experiments relies only on the primary scintillation photon signal. Energy reconstruction based on both the photon and electron signals yields a more accurate representation of search results. For a dark matter particle of mass m(chi) similar to 10 GeV, a nuclear recoil from a scattering event is more likely to be observed in the lower-left corner of the typical search box, rather than near the nuclear recoil calibration centroid. In this region of the search box, the actual nuclear recoil energies are smaller than the usual energy scale suggests, by about a factor of 2. Recent search results from the XENON100 experiment are discussed in light of these considerations.