  Light scalar fields can naturally couple disformally to matter fields.
Static, non-relativistic sources do not generate a classical field profile for
a disformally coupled scalar, and so such scalars are free from the constraints
on the existence of fifth forces that are so restrictive for conformally
coupled scalars. In this work we show that disformally coupled scalars can
still be studied and constrained through their microscopic interactions with
fermions and photons, both in terrestrial laboratories and from observations of
stars. The strongest constraint on the coupling scale comes from mono-photon
searches at the LHC and requires $M \gtrsim 10^2 \mbox{ GeV}$.
