Inelastic dark matter in light of DAMA/LIBRA

Inelastic dark matter, in which weakly interacting massive particle (WIMP)-nucleus scatterings occur through a transition to an excited WIMP state $\sim 100\mathrm{keV}$ above the ground state, provides a compelling explanation of the DAMA annual modulation signal. We demonstrate that the relative sensitivities of various dark matter direct detection experiments are modified such that the DAMA annual modulation signal can be reconciled with the absence of a reported signal at CDMS-Soudan, XENON10, ZEPLIN, CRESST, and KIMS for inelastic WIMPs with masses $O(100\mathrm{GeV})$. We review the status of these experiments, and make predictions for upcoming ones. In particular, we note that inelastic dark matter leads to highly suppressed signals at low energy, with most events typically occurring between 20 and 45 keV (unquenched) at xenon and iodine experiments, and generally no events at low ($\sim 10\mathrm{keV}$) energies. Suppressing the background in this high-energy region is essential to testing this scenario. The recent CRESST data suggest seven observed tungsten events, which is consistent with expectations from this model. If the tungsten signal persists at future CRESST runs, it would provide compelling evidence for inelastic dark matter, while its absence should exclude it.