London team installs mile-deep dark matter detector

About a quarter of the universe is made from a substance humans have never managed to detect. We only know about dark matter, which accounts for the 27 per cent of the universe not made of protons, neutrons and electrons, because of the gravitational effects we have observed on stars and galaxies. Several experiments are underway to try to directly detect dark matter, and LUX-ZEPLIN (LZ) is the latest to get going.

The particles which LZ is hunting are known as WIMPs (weakly interacting massive particles) and, as the name implies, they are characterised by their lack of any detectable interaction with normal matter.

“If WIMPS exist, billions of particles pass through your hand every second but to directly hunt this mysterious particle, we have to bury our detector deep underground to shield it from all the other particles which steadily bombard Earth’s surface,” explained Prof Cham Ghag, a physicist at UCL and collaborating scientist on LZ.