Inverse beta decay (IBD), \( {\overline{\nu}}_ep\to {e}^{+}n\left(\gamma \right) \) , is the main detection channel for reactor and supernova antineutrinos. To provide precise IBD cross sections at antineutrino energies \( {E}_{{\overline{\nu}}_e} \) ≳ 10 MeV, we evaluate radiative corrections from virtual pions within the framework of heavy baryon chiral perturbation theory. At leading order, only the pion isospin-breaking contributions are not suppressed by the electron mass. At next-to-leading order, besides recoil effects, only the Wilson coefficient c4 contributes to the kinematic dependence. However, its precise value is not relevant for IBD at relatively low energies since all next-to-leading order radiative corrections are relatively small. We find the kinematic dependence of the pion-induced QED radiative corrections at the level and below the uncertainty from the momentum dependence of the nucleon form factors. Our results enable sub-permille theoretical precision of charged-current elastic (anti)neutrino-nucleon scattering at (anti) neutrino energies Eν ≳ 10 MeV.
