how dark photons are changing our understanding of the universe

Dark photons are hypothetical particles that could 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 experimentally confirmed.

Scientists from the Fermi National Accelerator Laboratory at the US Department of Energy in during the experiment Dark SRFs demonstrate the unprecedented sensitivity of a research facility designed to search for the supposed particles – dark photons.

The scientists “trapped” ordinary, mass photons in devices called superconducting radio frequency resonators to track the transition of these photons into their supposed dark counterparts. The experiment was able to establish the world’s best bounding box for the existence of dark photons in a certain mass range. The results were recently published in Physical Review Letters.

“The dark photon is the counterpart of the photon we know and love, but with some differences,” said Roni Harnick, a researcher at Fermilab’s Center for Superconducting Quantum Materials and Systems and co-author of the study.

Dark matter, which makes up 85% of all matter, is filled with an unknown substance that scientists call “dark photons”. Just as an electron has copies that differ in some way, including a muon and a tau, a dark photon will be different from an ordinary photon and have mass. Theoretically, once they are produced, photons and dark photons can turn into each other at a certain rate given by the properties of the dark photon.

In the experiment, the scientists used two hollow, metal chambers to detect the transformation of an ordinary photon into a dark matter photon. Ordinary photons were stored in one chamber, while the other chamber remained empty. The researchers then looked for the appearance of photons in an empty chamber.

This experiment was the first example of the use of superconducting RF resonators for this kind of research. The resonators used in the experiment are hollow pieces of niobium. At ultra-low temperatures, these resonators effectively conserve photons.

Scientists can now use superconducting RF resonators with different 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 very high Q-factor resonators are used as extremely sensitive detectors,” said Anna Grassellino, director of the SQMS Center and co-lead of the experiment. “From the search for dark matter, to the study of gravitational waves, to fundamental tests of quantum mechanics, these world’s highest efficiency chambers will help us discover new physics.”