Researchers dig deep underground in hopes of finally observing dark matter
Retrieved on:
Wednesday, August 9, 2023
In the typical model, dark matter accounts for most of the gravitational attraction in the universe, providing the glue that allows structures like galaxies, including our own Milky Way, to form.
Key Points:
- In the typical model, dark matter accounts for most of the gravitational attraction in the universe, providing the glue that allows structures like galaxies, including our own Milky Way, to form.
- As the solar system orbits around the center of the Milky Way, Earth moves through a dark matter halo, which makes up most of the matter in our galaxy.
- One popular guess is that dark matter is a new type of particle, the Weakly Interacting Massive Particle, or WIMP.
Searching for WIMPs
- Over the past 30 years, scientists have developed an experimental program to try to detect the rare interactions between WIMPs and regular atoms.
- When particles pass through the detector, they may collide with xenon atoms, leading to a flash of light and the release of electrons.
- In LZ, two massive electrical grids apply an electric field across the volume of liquid, which pushes these released electrons to the liquid’s surface.
Reducing radioactivity
- Using this special titanium reduces the radioactivity in LZ, creating a clear space to see any dark matter interactions.
- In LZ, the central xenon detector lives inside two other detectors, called the xenon skin and the outer detector.
- These supporting layers catch radioactivity on the way in or out of the central xenon chamber.
The hunt continues
- In the result just published, using 60 days of data, LZ recorded about five events per day in the detector.
- That’s about a trillion fewer events than a typical particle detector on the surface would record in a day.
- By looking at the characteristics of these events, researchers can safely say that no interaction so far has been caused by dark matter.