Comment on “Amplifying nonresonant production of dark sector particles in scattering dominance regime”

In [M. Du , [] ] it has been argued that production of dark photons—hypothetical massive vectors—in nuclear reactors via mixing with the visible photons is considerably enhanced (by a factor of 10) due to Compton scattering of the latter. We revisit the production of dark photons in the reactor environment and find that although the scattering of photons indeed leads to a larger number of produced dark photons, the overall enhancement is considerably smaller than what has been obtained in the above article. Our findings are validated using simulations, which take into account oscillations between ordinary and visible photons and interaction of the latter with matter. The correction to the limit on mixing parameter between dark and visible photons is expected to be below 30% for all masses. Its application must be accompanied with an update on the original spectrum of photons produced in nuclear reactions inside the nuclear reactor.