Hidden photon CDM search at Tokyo
  We report on a search for hidden photon cold dark matter (HP CDM) using a
novel technique with a dish antenna. We constructed two independent apparatus:
one is aiming at the detection of the HP with a mass of $\sim\,\rm{eV}$ which
employs optical instruments, and the other is for a mass of
$\sim5\times10^{-5}\, \rm{eV}$ utilizing a commercially available parabolic
antenna facing on a plane reflector. From the result of the measurements, we
found no evidence for the existence of HP CDM and set upper limits on the
photon-HP mixing parameter $\chi$.
