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 2me 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 He4 abundance, which is completely insensitive to the small changes in the nuclear reaction rates. We also investigate the effect of vacuum polarization 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.
Bibliographical noteFunding Information:
We thank Alain Coc, Jean-Philippe Uzan, and Elisabeth Vangioni for discussions on the topic. C.P. thanks the Perimeter Institute (Waterloo, Ontario, Canada) and the University of Victoria (British Columbia, Canada), where this work was initiated for the former and completed for the latter. M.P. is grateful to the groups at IAP and Orsay for kind hospitality. Research at Perimeter Institute is supported by the Government of Canada through Industry Canada and by the Province of Ontario through the Ministry of Economic Development & Innovation.