Deep-sea detector could find first dark matter signals

25 November 2022

The KM3NeT neutrino detector at the bottom of the Mediterranean Sea is in principle also capable of seeing signals from dark matter from our own Galaxy.

This is according to a new study led by Nikhef researcher Suzan Basegmez du Pree, released this week. KM3NeT in the deep sea near Italy and France has excellent views of the center of the Milky Way.

Nikhef is one of the major partners in the KM3NeT project. In the project, hundreds of lines with thousands of light detectors are suspended on the sea floor that can show the tracks of passing neutrinos.

Unknown

Matter in the universe is divided into ordinary matter like stars and nebulae and dark matter that does not give off light but does about four-fifths of all gravity. What constitutes this dark matter is unknown. It is not the particles in the standard model.

Physicists are trying to find out what dark matter consists of with both direct measurements, with large underground detectors trying to find unknown particles arriving from the universe, and indirect measurements.

Indirect measurements look for known particles that could be created when dark matter annihilates. These could be antiparticles, light, and also neutrinos, the particles that instruments like KM3NeT can observe.

Neutrino signals

Basegmez du Pree has long been involved in a project aboard the International Space Station ISS, the AMS detector that searches for antimatter in the universe. AMS has found an excess events but cannot pinpoint their origin.

The KM3NeT researcher and a team of researchers in Amsterdam, Belgium, Poland and Hongkong therefore studied whether the fully built neutrino telescope can see enough indirect neutrino signals from the direction of the heart of the Milky Way in ten years of measurement.

This indeed seems to be the case, they conclude in an article on the web server Arxiv. KM3NeT turns out to be a factor of ten more sensitive than previously expected, especially for heavier dark matter particles. Any neutrino signal could thus help theorists in an explanation of the nature of dark matter.