Searching for Dark Matter and Dark Sectors

Rouven Essig, Stony Brook University (Principal Investigator) The overall objective of this proposal is to explore dark sectors, especially below the GeV-scale.  Dark sectors, which are particles that are not charged directly under the Standard Model forces, are an exciting theoretical possibility that could address several shortcomings of the Standard Model, including the existence of dark matter. The proposed research will: (1) Develop novel techniques and strategies for direct detection of sub-GeV dark matter, and provide the theoretical support for ongoing direct-detection efforts.  (2) Investigate new models of dark sectors, and derive new constraints from cosmology, astrophysics, and terrestrial experiments.  This includes an investigation of models with dark-matter self-interactions that could help form supermassive black holes in the early Universe.  (3) Explore new opportunities for dark-sector searches with existing and planned experiments.  This includes providing the theoretical support to two experiments the PI helped propose, the A' Experiment (APEX) and the Heavy Photon Search (HPS), both at Jefferson Lab.  (4) Search for a dark photon with APEX.  APEX will use an intense beam of electrons incident on a tantalum target, and will measure the invariant mass of electron-positron pairs to search for a dark-photon resonance.