QED corrections to the big-bang nucleosynthesis reaction rates
  We compute radiative corrections to nuclear reaction rates that determine the
outcome of the Big-Bang Nucleosynthesis (BBN). Any nuclear reaction producing a
photon with an energy above $2m_e$ must be supplemented by the corresponding
reaction where the final state photon is replaced by an electron-positron pair.
We find that pair production brings a typical $0.2 \%$ enhancement to photon
emission rates, resulting in a similar size corrections to elemental
abundances. The exception is $^4{\rm He}$ abundance, which is insensitive to
the small changes in the nuclear reaction rates. We also investigate the effect
of vacuum polarisation on the Coulomb barrier, which brings a small extra
correction when reaction rates are extrapolated from the measured energies to
the BBN Gamow peak energies.
