Plasmon phase space and millicharged particles
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 how 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.
Date: Thursday, 4 November 2021 Time: 11:30 Where: Université de Montréal Campus MIL, Local A-3502.1 et Zoom