South Pole observatory spots rare ghostly particles in old data

Scientists have found clear proof of tau neutrinos in data collected by the IceCube neutrino observatory between the years 2011 and 2020. Researchers reported this finding with a high certainty level of over 99.999999 percent. The IceCube facility sits at the Earth's South Pole and looks for tiny subatomic particles known as neutrinos. These particles are often called ghost particles because they rarely touch other matter. A human-sized detector would need to wait around a hundred years to catch even one neutrino interaction.

Observatory Design

The IceCube facility is the biggest neutrino telescope in the world. It covers a full cubic kilometre of space. The setup includes thousands of sensors placed more than 1.4 kilometres deep inside the ice along with detectors on the surface. When a neutrino hits the ice, it gives off radiation and charged particles. The deep sensors catch this light to figure out that a neutrino has passed by and to study its traits. The project was built and is run by the IceCube Collaboration, which brings together many global universities under the lead of the University of Wisconsin, Madison. While IceCube can spot some types of neutrinos right away, others need years of data collection before scientists can comb through the files to find them.

Context

Neutrinos travel across the universe almost completely undisturbed by stars, planets, and magnetic fields, which makes them very useful for studying deep space. Large detectors like IceCube must be built deep inside very clear ice or water to spot the faint flashes of light that happen during a rare particle collision. This kind of physics research helps scientists learn more about how the universe works at its most basic level.