We study a model of dark matter in which the hidden sector interacts with standard model particles via a hidden photonic portal. We investigate the effects of this new interaction on the hydrogen atom, including the Stark, Zeeman and hyperfine effect
s. Using the accuracy of the measurement of energy, we obtain an upper bound for the coupling constant of the model. We also calculate the contribution from the hidden photonic portal to the anomalous magnetic moment of the muon, which provides an important probe of physics beyond the standard model.
