Sweden (Stockholm University) Quest For The Particles Behind Dark Matter

Scientists have been pondering the existence of dark matter – matter that does not seem to interact with light – for almost a century. Thanks to a 27.5 million SEK grant, Jón Gudmundsson and his colleagues at Stockholm University can construct a new type of detector to find axions, a type of hypothetical particles that could constitute dark matter.

Top-down view of thin copper rods

Top-down view of the copper rods making up one of the Stockholm University prototypes being developed. Photo: Jón Gudmundsson.
“The concept for this new type of detector is based on a clever idea by research colleagues at our department. Thanks to the grant, we can now build a pathfinder experiment and assume a leadership role in this field on an international level”, says Jón Gudmundsson, Department of Physics, Stockholm University, leader of the project.

Since the 1930s, scientists have only been able to observe dark matter by studying how its gravity affects its surroundings, but no one knows what dark matter consists of yet. However, the most reasonable explanation for these observations is that dark matter consists of a type of particle that has not yet been discovered. A proposal for such a hypothetical particle, which could be dark matter, is called an axion and it is a new type of axion detector that the researchers at the Department of Physics have received a grant to develop.

Porträtt av Jón Gudmundsson

Jón Gudmundsson has received a grant from the Knut and Alice Wallenberg Foundation to study axions. Foto: Alexandre Adler.
“If we manage to detect axions, we not only have a possible explanation for dark matter, we also shed light on open questions in elementary particle physics”, says Jón Gudmundsson.

However, detecting axions has proven difficult. The new detector that the researchers are constructing does not track axions directly, instead it takes advantage of the fact that axions can be converted into other particles inside the detector. These in turn can be detected as light using ultra-sensitive receivers.

The project “Tuning into Dark Matter” has funding for five years. Principal investigator: Jón Gudmundsson. Co-investigators: Jan Conrad and Frank Wilczek, Department of Physics, Stockholm University.

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