Astrophysicists at the University of California, Berkeley, propose that the elusive dark matter particle, the axion, could be detected within seconds of a nearby supernova explosion. This breakthrough hinges on the detection of gamma rays produced during the first moments following the core collapse of a massive star.
The axion, a lightweight particle theorized to comprise a significant portion of the universe's dark matter, is expected to be generated in vast quantities shortly after a supernova. For detection to occur, the Fermi Gamma-ray Space Telescope must be aimed at the supernova at the time of the explosion, a scenario with roughly a 10% chance.
Should gamma rays be detected, researchers could determine the mass of the axion across a broad range of theoretical values, including those currently being tested in laboratory experiments. Conversely, a lack of detection would rule out many potential axion masses, significantly impacting ongoing dark matter research.
The last nearby supernova, 1987A, occurred in the Large Magellanic Cloud. At that time, the Solar Maximum Mission telescope was not sensitive enough to detect the expected gamma-ray intensity, leaving a gap in data.
Benjamin Safdi, a UC Berkeley associate professor, expressed concern that the next supernova may occur before appropriate detection instruments are in place. Researchers are currently discussing the feasibility of launching a full-sky gamma-ray satellite constellation, named GALAXIS, to ensure continuous monitoring of the sky for gamma-ray bursts.
The axion is a strong candidate for dark matter, fitting within the standard model of particle physics and potentially unifying gravity with quantum mechanics. The QCD axion, named after quantum chromodynamics, interacts weakly with matter and is theorized to transform into photons in strong magnetic fields.
Current experiments, including those by the ALPHA Consortium, aim to detect axions using laboratory setups. However, the UC Berkeley team suggests that neutron stars may serve as optimal environments for axion production, particularly during core-collapse supernovae. Their findings indicate that gamma rays produced in the vicinity of neutron stars could be detected, providing insights into the axion's properties.
In their recent paper, the researchers established limits on the mass of axion-like particles, predicting that a gamma-ray detection could confirm the QCD axion mass if it exceeds 50 microelectron volts. This would allow existing experiments to refocus on confirming the axion's characteristics.
The study underscores the importance of timely detection capabilities in the search for dark matter, as the next supernova could offer a crucial opportunity to advance our understanding of the universe.