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 $\sim \mathrm{e}\mathrm{V}$ which employs optical instruments, and the other is for a mass of $\sim 5\times {10}^{-5}\mathrm{e}\mathrm{V}$ 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 $\chi$.