Hunting Dark Photons with a Mirror Telescope ⚡ экспресс
We present the first results from the Dandelion experiment on the directional search for dark matter in the form of dark photons with masses around 1 meV. A spherical mirror converts dark photons into standard millimeter-wave photons, which are detected by an array of 221 kinetic inductance detectors (KIDs) in the KISS-NIKA camera, cooled to 150 mK and operating at 150–350 GHz. Analysis of 1480 minutes of data accounting for modulation due to Earth’s rotation revealed the main noise source as fluctuations in thermal background and scattered light. To suppress these, templates were constructed using principal component analysis (PCA) based on detector measurements outside the expected field-of-view trajectory of the dark photons. No signal was detected, allowing us to set new upper limits on kinetic mixing χ for the mass range 0.6–1.4 meV. These are the first constraints on dark photons as a dark matter candidate obtained with a KID array in the millimeter-wave band.
The universe is held together by an invisible scaffolding of dark matter. Part of it could be dark photons, ghostly copies of light that pass right through matter. The Dandelion experiment turned a spherical mirror into a super-sensitive ear: it gathers dark photons and translates them into the language of radio waves. 221 detectors chilled nearly to absolute zero listened for that whisper for 1480 minutes.
The trouble is, the whisper gets drowned out by a roar — thermal noise from the room and electronics. Physicists used spectral analysis as noise cancellation: they recorded the background from sensors not aimed at the target and subtracted it from the main data.
The silence remained absolute. But it’s not useless: the experiment, for the first time using quantum detectors for photometry, set the tightest limit yet on how likely dark photons are to turn into ordinary light in the mass range of 0.6–1.4 meV.
🎯 A dark photon with a mass of 1 meV is half a million times lighter than an electron — the lightest particle with nonzero mass.