Plasmon production from dark matter scattering
Jonathan Kozaczuk (Department of Physics, University of California, San Diego, California 92093, USA); Tongyan Lin (Department of Physics, University of California, San Diego, California 92093, USA)
We present a first calculation of the rate for plasmon production in semiconductors from nuclei recoiling against dark matter. The process is analogous to bremsstrahlung of transverse photon modes, but with a longitudinal plasmon mode emitted instead. For dark matter in the 10 MeV—1 GeV mass range, we find that the plasmon bremsstrahlung rate is 4–5 orders of magnitude smaller than that for elastic scattering, but 4–5 orders of magnitude larger than the transverse bremsstrahlung rate. Because the plasmon can decay into electronic excitations and has characteristic energy given by the plasma frequency , with in Si crystals, plasmon production provides a new signature and method to detect nuclear recoils from sub-GeV dark matter.
