Photodisintegration of deuterium and big bang nucleosynthesis

Photodisintegration cross sections were measured for deuterium with Laser-Compton scattering $\gamma$ beams at seven energies near threshold. Combined with the preceding data, ${R\left(E\right)=N}_a\sigma v$ for the $p(n,\gamma )\mathrm{D}$ reaction is for the first time evaluated based on experimental data with 6% uncertainty in the energy region relevant to the big bang nucleosynthesis (BBN). The result confirms the theoretical evaluation on which the BBN in the precision era relies.