Nov 23 – 25, 2020
Europe/Stockholm timezone

Search for Light Dark Matter using a Primary Electron Beam

Nov 23, 2020, 2:30 PM


Geoffrey Mullier (Lund University (SE))


The constituents of dark matter are still unknown, and the viable possibilities span a very large mass range. Specific scenarios for the origin of dark matter sharpen the focus on a narrower range of masses: the natural scenario where dark matter originates from thermal contact with familiar matter in the early Universe requires the DM mass to lie within about an MeV to 100 TeV. Considerable experimental attention has been given to exploring Weakly Interacting Massive Particles in the upper end of this range (few GeV – TeV), while the region MeV to ~GeV is largely unexplored. Most of the stable constituents of known matter have masses in this lower range, tantalizing hints for physics beyond the Standard Model have been found here, and a thermal origin for dark matter works in a simple and predictive manner in this mass range as well. It is therefore a priority to explore. If there is an interaction between light DM and ordinary matter, as there must be in the case of a thermal origin, then there necessarily is a production mechanism in accelerator-based experiments. The most sensitive way, (if the interaction is not electron-phobic) to search for this production is to use a primary electron beam to produce DM in fixed-target collisions. The Light Dark Matter eXperiment (LDMX) is a planned electron-beam fixed-target missing-momentum experiment that has unique sensitivity to light DM in the sub-GeV range. The experiment requires a primary electron beam. In a first phase, this will be delivered by LCLS-II at SLAC into a dedicated beamline under construction. An even more powerful facility at CERN have been proposed. The Swedish engagement in LDMX is part of the Wallenberg project KAW-LDM. This contribution will give a brief overview of the theoretical motivation, the main experimental challenges and how they are addressed as well as projected sensitivities, and will focus on progress made over the past year.

Abstract Track Cross-field collaborative initiatives

Primary author

Geoffrey Mullier (Lund University (SE))

Presentation materials