Precise WIMP Dark Matter Abundance and Standard Model Thermodynamics
  A weakly interacting massive particle (WIMP) is a leading candidate of the
dark matter. The WIMP dark matter abundance is determined by the freeze-out
mechanism. Once we know the property of the WIMP particle such as the mass and
interaction, we can predict the dark matter abundance. There are, however,
several uncertainties in the estimation of the WIMP dark matter abundance. In
this work, we focus on the effect from Standard Model thermodynamics. We
revisit the estimation of the WIMP dark matter abundance and its uncertainty
due to the equation of state (EOS) in the Standard Model. We adopt the
up-to-date estimate of the EOS of the Standard Model in the early Universe and
find nearly 10% difference in the 1-1000 GeV dark matter abundance, compared to
the conventional estimate of the EOS.
