  Extra "hidden" U(1) gauge factors are a generic feature of string theory that
is of particular phenomenological interest. They can kinetically mix with the
Standard Model photon and are thereby accessible to a wide variety of
astrophysical and cosmological observations and laboratory experiments. In this
paper we investigate the masses and the kinetic mixing of hidden U(1)s in LARGE
volume compactifications of string theory. We find that in these scenarios the
hidden photons can be naturally light and that their kinetic mixing with the
ordinary electromagnetic photon can be of a size interesting for near future
experiments and observations.
