User:Nealweiner

Inelastic Dark Matter was a theory of dark matter proposed by David Tucker-Smith and Neal Weiner in 2001 to explain the apparent discrepancy between DAMA and CDMS. They argued that if the dark matter transitioned to an excited state which was $$m_\chi^* - m_\chi = \delta \approx \beta^2/2m_\chi$$ heavier than the ground state, the kinematics would be such that DAMA and CDMS could be reconciled. Updates from additional experiments, including XENON10, ZEPLINI, ZEPLINII, CRESST, KIMS and CDMS-Soudan all could be reconciled with the positive results of DAMA quite simply. This arose from three basic effects:

First, the kinematical differences require a minimum velocity in order to scatter at all.

Second, because the scatters sample a high velocity portion of the Maxwell-Boltzmann distribution where it changes exponentially rapidly, the modulation rate is enhanced (favoring modulated experiments over unmodulated experiments)

Third, the lowest energy events are suppressed or zero, with the signal turning on at higher energies. This favors high threshold experiments over low threshold experiments.

Early models were of a mixed sneutrino or a fourth-generation neutrino (both interacting via a Z-boson), and, recently, a neutralino in R-symmetric theories. More recently, in light of the PAMELA evidence for a positron excess, it was suggested that inelastic dark matter scattering could arise via a new force carrier with mass in the ~ 100 MeV range.