Nuclear Kinetic Equilibrium During Big Bang Nucleosynthesis
  Sasankan et al, have recently claimed that there are significant deviations
in the phase-space distributions of the kinetic energies of nuclei from the
Maxwell-Boltzmann form usually assumed in BBN, and further, that these
deviations lead to big changes in the predicted light-element abundances.
Solving the relativistic Boltzmann equation perturbatively, we explicitly show
that these deviations are not 20% as claimed, but rather are about 10^-17 in
size and hence cannot significantly alter the predicted light-element
abundances. We discuss and compute two related effects: O(0.1%) corrections to
the kinetic distributions of nuclei that arise from small relativistic
corrections to the MB distribution and a much smaller effect, nuclear kinetic
drag, which arises from the heat transferred from the EM plasma to nuclei that
is needed to maintain kinetic equilibrium.
