Ms
Tracy Slatyer
(Harvard University)
A new force in the dark sector, with GeV-scale force carriers, can change the expected properties of SUSY WIMP dark matter in significant ways. The annihilation cross section at low velocities is boosted by a Sommerfeld enhancement, perhaps by 2 or 3 orders of magnitude; the WIMP annihilates to the new force carrier, which immediately
decays to light particles, bypassing constraints from antiprotons and pi-0 gammas;
and excited states for the WIMP are naturally generated, making inelastic scattering
possible. These are exactly the properties needed to explain recent results
from cosmic ray measurements and the DAMA direct detection experiment,
without violating the many tight constraints from other experiments.
I will review the current status of the data, show how it can be explained with
such a WIMP, and discuss the "smoking gun" signals expected in future
data sets (Fermi LAT, CDMS, CRESST, LUX, etc.).
Recently measured anomalous excesses of 10-1000 GeV electron and positron cosmic rays have motivated WIMP models with large annihilation cross sections, especially when the relative velocity of the annihilating particles is low. I will show that these models are already uniformly close to the 95% confidence limits from WMAP, and the recently launched Planck satellite will be capable of ruling out a wide range of DM explanations for the cosmic ray excesses. In models of dark matter with Sommerfeld-enhanced annihilation, where sigma v rises with decreasing WIMP velocity until some saturation point, WMAP places strong constraints on the allowed parameter space, with implications for collider searches and annihilation signatures from substructure.
Summary
A new force in the dark sector, with GeV-scale force carriers, can change the expected properties of SUSY WIMP dark matter in significant ways. The annihilation cross section at low velocities is boosted by a Sommerfeld enhancement, perhaps by 2 or 3 orders of magnitude; the WIMP annihilates to the new force carrier, which immediately
decays to light particles, bypassing constraints from antiprotons and pi-0 gammas;
and excited states for the WIMP are naturally generated, making inelastic scattering
possible. These are exactly the properties needed to explain recent results
from cosmic ray measurements and the DAMA direct detection experiment,
without violating the many tight constraints from other experiments.
I will review the current status of the data, show how it can be explained with
such a WIMP, and discuss the "smoking gun" signals expected in future
data sets (Fermi LAT, CDMS, CRESST, LUX, etc.).
