News & Events

Speaker: Katelin Schutz (McGill University)

Title: Plasmon phase space and millicharged particles

Abstract: Astrophysical plasmas can be an abundant source of particles with a small coupling to photons (“millicharged particles” or MCPs), for instance in dark sectors with a kinetically mixed U(1). In many situations, the decay of plasmons (photons with an in-medium effective mass) is the most efficient process for generating MCPs. In this talk, I will discuss two distinct examples: the production of gravitationally bound MCPs in the sun and the freeze-in of dark matter in the early Universe. In both cases, the unique phase space imparted by the plasmon decay process is crucial for determining observable signatures. In the former case, I will show some preliminary results indicating that gravitationally bound MCPs from the sun may be detectable with an experimental setup that coherently deflects the solar MCP wind, generating an oscillating electric field in a shielded detector. In the latter case, I will show that dark matter freeze-in from plasmon decay may be detectable through its cosmological clustering and through a drag effect imparted on the photon-baryon fluid prior to recombination.

McDonald Insititute seminars bring together experimental and theoretical astroparticle physicists and astronomers. They are held approximately fortnightly, September to November and January to March, and on an ad hoc basis outside of term. They currently take place on Thursdays at 3:30 PM in STI 501 and/or on Zoom. Contact Aaron Vincent if you would like to attend.

https://www.physics.queensu.ca/facultysites/vincent/seminars/