On the Direct Detection of Dark Matter in the Stratosphere

We investigate the prospects for direct detection of Dark Matter (DM) particles, such as dark photons, incident on the upper atmosphere. A recent work relates the burst-like temperature excursions in the stratosphere at heights of ~38-47 km with incident invisible streaming matter. Surprisingly, dark photons match the reasoning presented in that work provided they constitute part of the local DM density. Dark photons mix with real photons with the same total energy without the need for an external field as would be required for instance for axions. Furthermore, the ionospheric plasma column above the stratosphere can enhance the dark photon to photon conversion due to resonance. The stratosphere is easily accessible via balloon flights. Balloon missions with up to a few tons of payload can be readily assembled to operate for 1-2 months at such atmospheric heights making for realistic short term endeavor of on-site direct DM search following this proposal. The approach need not be limited to streaming dark photons as other DM candidates might be searched simultaneously. Combining different types of measurements in a multi-band detector system and/or relating such investigations with other concurrent atmospheric observations, e.g. from space, may be proven to be the missing new approach in direct DM detection.