Dark photons are hypothetical particles that can be associated with dark matter – a mysterious substance that makes up 85% of all matter in the Universe. However, their existence has not yet been confirmed experimentally.
Scientists from the Laboratory of National Accelerator Fermi at the US Department of Energy conducted the Dark SRF experiment to demonstrate the unprecedented sensitivity of their research installation in the search for dark photons. The experiment aimed to track the transition of ordinary photons to alleged dark analogues using superconducting radio frequency resonators. The results, which establish the best limiting frame in the world for the existence of dark photons in a certain mass range, were recently published in Physical Review Letters. [source]
“Dark photons are analogues of the photons we know and love, but with some differences,” said Roni Harnik, a researcher from the center of superconducting quantum materials and Fermilab systems, and co-author of the study.
Dark matter, which constitutes 85% of all matter, is believed to be composed of an unknown substance dubbed “dark photons”. Similar to how the electron has copies with different properties such as the Muon and Tau, dark photons differ from ordinary photons by having mass. Theoretically, photons and dark photons can convert into each other at a specific speed determined by the properties of a dark photon.
In the experiment, scientists utilized two metal chambers to detect the conversion of conventional photons into photons of dark matter. One chamber stored ordinary photons, while the other remained empty. The researchers then observed the appearance of photons in the empty chamber as evidence of the conversion.
This experiment marked the first instance of employing superconducting radio frequency resonators for this type of research. These resonators, made of niobium, effectively retain photons at superconducting temperatures.
Scientists can now employ superconducting radio frequency resonators with various resonant frequencies to cover different parts of the potential mass range for dark photons.
“The Dark SRF experiment has paved the way for a new class of experiments at the SQMS center, where these highly sensitive resonators with a very high Q factor are utilized as detectors,” stated Anna Grassellino, the director of the SQMS center and experimental leader. She added, “From the search for dark matter to the study of gravitational waves and fundamental checks