Dark matter, an enigmatic component of our universe, remains largely invisible to conventional telescopes. However, a team of Chinese researchers have found a promising way to detect one of the prime candidates of dark matter – dark photons.
Researchers at Tsinghua University, the Purple Mountain Observatory, and Peking University have proposed a novel method to detect dark photons, a hypothesized component of dark matter, using radio telescopes. Their recent study published in Physical Review Letters, explores the possibility of using the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China for this purpose. The team’s approach could revolutionize the way we search for dark matter.
Understanding the Enigma: Dark Matter and Dark Photons
Dark matter, making up around 85% of the universe, remains undetectable through conventional means due to its interaction, or lack thereof, with light. Researchers have long speculated about “dark photons” – hypothetical particles akin to the photons in our visible world, which could carry a force in dark matter.
Breaking New Ground: An Innovative Approach
Led by Haipeng An, the research team expanded on their prior work, which explored the conversion of dark photons into photons in the solar corona. They aimed to utilize the free electrons in a radio telescope to induce electromagnetic signals and capture these signals using the FAST radio telescope.
The Curious Case of the Spherical Reflector
The team soon realized that due to the non-relativistic nature of dark matter, the reflector in such telescopes would need to be spherical and the signal receiver should be at the center. Existing telescopes like FAST are designed with parabolic dishes, and the receiver is placed at the focus point. This meant that signals induced by dark photons wouldn’t concentrate at the receiver.
A Turning Point: The Movable Receiver
Following a deep dive into how the FAST telescope operates, An proposed that the movable receiver could collect electromagnetic signals from different locations. Comparing the collected signals with theoretical predictions could enhance the sensitivity of the telescopes to dark photon-induced signals.
Potential for Discovery
The research team found that even with the non-focused nature of the dark photon induced signal, the extraordinary sensitivity of the FAST telescope surpasses the cosmic microwave background (CMB) constraint. This implies that if dark matter consists of dark photons and is within the right mass region, the FAST telescope could potentially discover it.
Trials and Triumphs: Analyzing the Data
The team analyzed observation data from the FAST telescope, and they placed stringent bounds on the dark photon model in the 1–1.5 GHz frequency range. They found that the potential sensitivity of LOFAR telescope and the future Square Kilometre Array (SKA) telescope could possibly discover dark photon dark matter.
Building on this breakthrough, the research team plans to search for dark photon dark matter signals in data from LOFAR and MeerKAT telescopes. They also aim to apply this method to search for axion dark matter, another ultralight dark matter candidate. This research could open up new areas in radio astronomy and revolutionize our understanding of the universe.