We study the effects of dark-matter annihilation during the epoch of big-bang nucleosynthesis on the primordial abundances of light elements. We improve the calculation of the light-element abundances by taking into account the effects of anti-nucleons emitted by the annihilation of dark matter and the interconversion reactions of neutron and proton at inelastic scatterings of energetic nucleons. Comparing the theoretical prediction of the primordial light-element abundances with the latest observational constraints, we derive upper bounds on the dark-matter pair-annihilation cross section. Implication to some of particle-physics models are also discussed.
Kawasaki, M., Kohri, K., Moroi, T., & Takaesu, Y. (2015). Revisiting big-bang nucleosynthesis constraints on dark-matter annihilation. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 751, 246–250. https://doi.org/10.1016/j.physletb.2015.10.048