Inelastic Dark Matter and DAMA/LIBRA: An Experimentum Crucis

Understand

The DAMA/LIBRA collaboration has detected an annual modulation of the recoil rate in NaI crystals with the phase expected for WIMP scattering events.

• This signal is dramatically inconsistent with upper limits from other experiments for elastically scattering weak-scale WIMPs.
• However, the results are compatible for the case of inelastic dark matter (iDM).
• The iDM theory, as implemented by Tucker-Smith and Weiner, constrains the WIMP to a tight contour in sigma_n-delta space, where delta is the mass difference between the ground state and excited WIMPs.