The Dark SRF experiment conducted at Fermilab has brought groundbreaking advancements in the search for the theoretical dark photons. Utilizing superconducting radio frequency (SRF) cavities, the scientists captured regular photons and studied their conversion into dark photons. The study established the most rigorous constraint to date on the presence of dark photons within a specific mass range.
Scientists from the Fermi National Accelerator Laboratory conducted the Dark SRF experiment and achieved an unprecedented level of sensitivity in the quest for dark photons. By employing superconducting radio frequency (SRF) cavities in an innovative manner, they can now delve into a variety of potential mass ranges for these elusive particles, further pushing our understanding of dark matter.
The Dark SRF experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory exhibited an extraordinary sensitivity in an experimental setup designed to search for theoretical particles known as dark photons.
Utilizing superconducting radio frequency cavities, researchers captured ordinary, massless photons to study their transformation into their hypothesized dark sector counterparts. The experiment has set the world’s strongest limit on the existence of dark photons within a certain mass range, as recently published in Physical Review Letters.
Roni Harnik, a researcher at the Fermilab-hosted Superconducting Quantum Materials and Systems Center and co-author of the study, described the dark photon as a similar entity to the known photon, with slight differences.
Regular photons make up the light that enables us to observe ordinary matter in our world. However, dark matter, an unknown substance, constitutes 85% of all matter, with the remaining matter only accounting for a small fraction. The Standard Model that illustrates known particles and forces is incomplete.
In the simplest theorist version, one undiscovered dark matter particle could account for all the dark matter in the universe. However, it is widely believed that the dark sector might contain various particles and forces, some of which could have concealed interactions with regular matter particles and forces.
Similar to how an electron has variants, including the muon and tau, the dark photon would differ from the regular photon and possess mass. Theoretically, once produced, photons and dark photons could convert into each other at a specific rate dictated by the properties of the dark photon.
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Innovative Application of SRF Cavities
Scientists conduct a light-shining-through-wall experiment to search for dark photons. They utilize two metallic, hollow cavities to detect the transformation of an ordinary photon into a dark matter photon. Regular photons are stored in one cavity while the other cavity is left empty. Scientists then watch for the appearance of photons in the empty cavity.
Researchers at the SQMS Center, Fermilab, have extensive experience working with SRF cavities, primarily used in particle accelerators. They have recently used SRF cavities for other purposes such as quantum computing and dark matter searches due to their capacity to store and control electromagnetic energy efficiently.
Alexander Romanenko, SQMS Center quantum technology thrust leader, recognized the potential of using SRF cavities to demonstrate greater sensitivity than cavities used in previous experiments. This marked the first instance of utilizing SRF cavities in a light-shining-through-wall experiment.
Romanenko and his team used hollow niobium chunks as SRF cavities. These cavities, when cooled to ultralow temperature, store photons or packets of electromagnetic energy very well. For the Dark SRF experiment, they cooled the SRF cavities in liquid helium to about 2 K, nearly absolute zero, at which temperature electromagnetic energy seamlessly flows through niobium, making these cavities highly efficient at storing photons.
Researchers can now employ SRF cavities with different resonance frequencies to cover various parts of the potential mass range for dark photons. This is because the peak sensitivity on the mass of the dark photon is directly connected to the frequency of the regular photons stored in one of the SRF cavities.
The experiment’s success and its coverage of new parameter regions for the dark photon’s mass suggest a bright future for the search for dark matter using SRF cavities. It has also paved the way for a new class of experiments at the SQMS Center where these high-efficiency cavities are used as highly sensitive detectors to help uncover hints of new physics, from dark matter to gravitational waves searches, to fundamental tests of quantum mechanics.
The study titled “Search for Dark Photons with Superconducting Radio Frequency Cavities” by A. Romanenko, R. Harnik, A. Grassellino, and others was published in Physical Review Letters on 26 June 2023.
Frequently Asked Questions (FAQs) about Dark SRF experiment
What is the Dark SRF experiment?
The Dark SRF experiment is a scientific investigation conducted at the Fermi National Accelerator Laboratory. It uses Superconducting Radio Frequency (SRF) cavities to trap and study photons, with a focus on their hypothetical transformation into dark photons.
What are dark photons?
Dark photons are theoretical particles that are similar to photons, the particles of light we know, but with some variations. They are hypothesized to have mass and could be related to the elusive dark matter in the universe.
How do researchers search for dark photons in the Dark SRF experiment?
Researchers in the Dark SRF experiment conduct a “light-shining-through-wall” experiment. This involves using two hollow, metallic cavities – one filled with regular photons and one left empty. Scientists then monitor the empty cavity for the emergence of photons, which would indicate the transformation of regular photons into dark photons.
What does the Dark SRF experiment contribute to the field of physics?
The Dark SRF experiment has achieved unprecedented sensitivity in the search for hypothetical dark photons, thereby pushing the boundaries of our understanding of dark matter. It has also established the most stringent constraint yet on the existence of dark photons within a specific mass range.
What role do Superconducting Radio Frequency (SRF) cavities play in the Dark SRF experiment?
SRF cavities are used in the Dark SRF experiment to trap regular photons and investigate their potential transformation into dark photons. These cavities, made of niobium and cooled to ultralow temperatures, are extremely efficient at storing photons, thereby enhancing the sensitivity of the experiment.
More about Dark SRF experiment
- Fermi National Accelerator Laboratory
- Superconducting Quantum Materials and Systems Center (SQMS)
- Dark Matter
- Superconducting Radio Frequency (SRF) Technology
- Physical Review Letters
- Standard Model of Particle Physics
6 comments
I’m a physics student and this just blows my mind. we’re talking about particles that could be part of the majority of our universe…and we’ve never seen them. just wow!
This is really mind-blowing stuff! Just imagine, there might be an entirely different type of photon out there that we havent discovered yet. Science is so cool!!
All this talk about dark matter and dark photons makes my head spin. but, its cool to know there are folks out there who are able to understand it and push the envelope. Keep it up!
Its like finding a needle in a haystack, but the needle and the haystack are invisible! Kudos to these scientists for pushing the boundaries of what we know.
I’m no physicist, but this article was really interesting. I wonder how this dark matter search is gonna affect us in the future…?
As far as I can tell, this is like fishing in the dark. Literally. Except the fish might not exist. Amazing stuff.