  Mirror dark matter, where dark matter resides in a hidden sector exactly
isomorphic to the standard model, can be probed via direct detection
experiments by both nuclear and electron recoils if the kinetic mixing
interaction exists. In fact, the kinetic mixing interaction appears to be a
prerequisite for consistent small scale structure: Mirror dark matter halos
around spiral galaxies are dissipative - losing energy via dark photon
emission. This ongoing energy loss requires a substantial energy input, which
can be sourced from ordinary supernovae via kinetic mixing induced processes in
the supernova's core. Astrophysical considerations thereby give a lower limit
on the kinetic mixing strength, and indeed lower limits on both nuclear and
electron recoil rates in direct detection experiments can be estimated. We show
here that potentially all of the viable parameter space will be probed in
forthcoming XENON experiments including LUX and XENON1T. Thus, we anticipate
that these experiments will provide a definitive test of the mirror dark matter
hypothesis.
