HET Brown Bag | Respect the ELDER: New Thermal Target for Dark Matter Direct Detections and Going Beyond with Astrophysical Signatures

A less explored procedure for a thermal relic to reach its current abundance is that it first elastically (thermally) decouples from the relativistic species before it freezes out from the number-changing processes. Here we present a novel dark matter (DM) candidate, an Elastically Decoupling Relic (ELDER), which is a thermal relic whose present-day abundance is determined by the cross-section of its elastic scattering on Standard Model particles, based on the aforementioned procedure.

Assuming that this scattering is mediated by a kinetically mixed dark photon, the ELDER scenario makes robust predictions for electron-recoil direct-detection experiments, as well as for dark photon searches. These predictions are independent of the details of interactions within the dark sector. The ELDER predictions provide a target region that will be almost entirely accessible to the next generation of searches for sub-GeV dark matter and dark photons.

If time permits, I will talk briefly about optical, gravitational, and radio signatures of DM-induced neutron star (NS) Implosions. The Astrophysical signatures (NS-NS mergers included!) are ways to go orders beyond the DM direct-detection limits.

This talk is based on Phys. Rev. Lett. 116, 221302 (arXiv:1512.04545), JHEP, 08:078, 2017 (arXiv:1706.05381), and arXiv:1706.00001