High Energy Physics Seminar: Dr. Gordan Krnjaic, Fermilab  Add To Calendar

  • Date(s): Wednesday, 3/21 11:00 AM to Wednesday, 3/21 12:00 PM
  • Speaker: Dr. Gordan Krnjaic
  • Host: Prof. James Unwin
  • Campus Address: 2214 SES
Title: Discovering or Falsifying sub-GeV Thermal Dark Matter

Abstract: This talk covers the theoretical features and experimental status of thermal dark matter (DM) with mass below the electroweak scale (M_DM << 100 GeV).  In this class of models, dark and visible matter are initially in thermal equilibrium during the early universe when the DM is relativistic (T_photons  >> M_DM). During this epoch, dark and visible matter annihilate into each other at equal rates and both number densities are calculable from equilibrium thermodynamics.  However, as Hubble expansion cools the universe, the annihilation rates fall out of equilibrium and the co-moving DM number density becomes fixed to its value when equilibrium is lost. Thus, these models predict a firm relationship between the dark-visible annihilation cross section and the cosmic DM abundance, which implies a sharp sensitivity target for a variety of  novel, accelerator based search techniques. It is found that a small set of future experiments based on these new techniques can decisively discover or falsify nearly all predictive models of thermal DM below the electroweak scale.

HEP Mar21 Krnjaic flyer