$ np \leftrightarrow d\gamma $ reactions calculated up to $E_{\gamma}=20$ MeV

We calculate the electromagnetic dipole transition cross sections for the $np \rightarrow d\gamma$ and $d\gamma \rightarrow np$ reactions over a broad range of energies. We use the LENPIC nucleon-nucleon interaction obtained from chiral effective field theory ($\chi$EFT) up to next-to-next-to-next-to-next-to-leading order (N4LO) and effective electromagnetic dipole transition operators obtained from the same $\chi$EFT up to N2LO. Our results agree with existing experiments. We get results at energies for which experimental data and/or modern theoretical calculations have not been reported. In this study, we utilize a new approach, namely, our adaptation of the Efros [V. D. Efros, Phys. Rev. C 99, 034620 (2019)] method that is prospective for future many-body applications in calculations of bound and continuum state wave functions.