Search for Dark Photon Dark Matter in the Mass Range <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mn>74</mml:mn><mml:mi>–</mml:mi><mml:mn>110</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi mathvariant="normal">μ</mml:mi><mml:mi>eV</mml:mi></mml:mrow></mml:math> with a Cryogenic Millimeter-Wave Receiver
S. Kotaka, S. Adachi, R. Fujinaka, S. Honda, H. Nakata, Y. Seino, Yoshinori Sueno, T. Sumida, J. Suzuki, O. Tajima, S. Takeichi
Abstract
We search for the dark photon dark matter (DPDM) using a cryogenic millimeter-wave receiver. DPDM has a kinetic coupling with electromagnetic fields with a coupling constant of $\ensuremath{\chi}$ and is converted into ordinary photons at the surface of a metal plate. We search for signal of this conversion in the frequency range 18--26.5 GHz, which corresponds to the mass range $74--110\text{ }\text{ }\mathrm{\ensuremath{\mu}}\mathrm{eV}/{c}^{2}$. We observed no significant signal excess, allowing us to set an upper bound of $\ensuremath{\chi}<(0.3\ensuremath{-}2.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$ at 95% confidence level. This is the most stringent constraint to date and tighter than cosmological constraints. Improvements from previous studies are obtained by employing a cryogenic optical path and a fast spectrometer.