  In this paper we study various particle physics effects of a light, scalar
dark energy field with chameleon-like couplings to matter. We show that a
chameleon model with only matter couplings will induce a coupling to photons.
In doing so, we derive the first microphysical realization of a chameleonic
dark energy model coupled to the electromagnetic field strength. This analysis
provides additional motivation for current and near-future tests of axion-like
and chameleon particles. We find a new bound on the coupling strength of
chameleons in uniformly coupled models. We also study the effect of chameleon
fields on Higgs production, which is relevant for hadron colliders. These are
expected to manufacture Higgs particles through weak boson fusion, or
associated production with a Z or W. We show that, like the Tevatron, the LHC
will not be able to rule out or observe chameleons through this mechanism,
because gauge invariance of the low energy Lagrangian suppresses the
corrections that may arise.
