  We explore a novel IR phase of electromagnetism and place constraints on it.
The usual IR modification of electromagnetism, the Higgs phase, involves adding
a photon mass for the gauge field $A_\mu$, which screens electric fields and
confines magnetic fields. We explore the confined phase resulting from adding a
mass term for the dual photon, which screens magnetic fields and confines
electric fields. We study the theory of a dual photon mass and argue that it is
a consistent effective field theory. We then elucidate the phenomenological
consequences of such a mass term and derive constraints on it. As the current
constraints come with large uncertainties, we also propose a few new searches
for a dual photon mass term.
