2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/179534Leading-order electromagnetic loop corrections to the one-pion-exchange potential are computed within the framework of chiral perturbation theory. These corrections generate an effective nucleon-nucleon potential, $V_{πγ}$, which supplements the sum of OPEP and the nucleon-nucleon Coulomb potential. This potential is charge dependent and its construction is demonstrated to be gauge invariant. The potential $V_{πγ}$ has been included in the Nijmegen partial-wave analysis of np data. A particular renormalization scheme is chosen that leads to a negligible change in the charged-piNN coupling constant and in the np 1S0 scattering length and effective range.10 pages, latex, 1 figure -- Submitted to Phys. Rev. Lett. -- epsfig.sty requiredNuclear Theorytext