  Dark-matter particles like neutralinos should decouple from the hot cosmic
plasma at temperatures of about 40 GeV. Later they can annihilate each other
into standard-model particles, which are injected into the dense primordial
plasma and quickly loose energy. This process is similar to jet quenching in
ultrarelativistic heavy-ion collisions, actively studied in RHIC and LHC
experiments. Using empirical information from heavy-ion experiments I show that
the cosmological (anti)quark and gluon jets are damped very quickly until the
plasma remains in the deconfined phase. The charged hadron and lepton jets are
strongly damped until the recombination of electrons and protons. The
consequences of energy transfer by the annihilation products to the cosmic
matter are discussed.
