Researches at Stockholm University are getting closer to light dark-matter particle models. Observations rule out some axion-like particles in the quest for the content of dark matter. The article is now published in the Physical Review Letters.
Physicists are still struggling with the conundrum of identifying more than 80 percent of the matter in the universe. One possibility is that it is made up of extremely light particles that weigh less than a billionth of the mass of an electron. These particles are often called axion-like particles (ALPs). Since ALPs are hard to find, the researchers have not yet been able to test different types of ALPs that could be a constituent of dark matter.
For the first time, the researchers used data from NASA's gamma-ray telescope on the Fermi satellite to study light from the central galaxy of the Perseus galaxy cluster in the hunt for ALPs. The researchers found no traces of ALPs and for the first time, the observations were sensitive enough to exclude certain types of ALPs (ALPs can only constitute dark matter if they have certain characteristics).
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