|The Ash River Facility|
|The facility in Tower Soudan|
The co-winners of the 2015 Nobel Prize in physics, Takaaki Kajita of Japan and Arthur B. McDonald of Canada, are well known to UMD Professor Alec Habig.
Kajita and McDonald shared the prize for their game-changing discoveries about neutrinos. The Nobel committee that bestowed the prize explained their research this way: "Scientists had theoretically calculated the number of neutrinos that were created in the nuclear reactions that make the sun shine, but when carrying out measurements on Earth, up to two-thirds of the calculated amount was missing. Where did the neutrinos go?"
Habig worked on the question, "Where did the neutrinos go?" with Kajita. In 1996, when Habig was a postdoctoral student, he joined a research team led by Kajita and Ed Kearns, a Boston University physicist, spending many months in Japan. There, Habig assisted Kajita on the work at the Super-Kamiokande detector — built in a zinc mine.
For several decades, physicists have been trying to solve this complex mystery around neutrinos. Thousands of billions of neutrinos are flying through our body every second. The team looked at neutrinos coming from cosmic rays to see if the particles changed on their way to the detector in Japan.
Habig worked with Kajita to discover that neutrinos, the second most numerous subatomic particle in the Universe, shift identities in space. Kajita and his team found that neutrinos didn't disappear at all, but fooled observers by changing identities — from one of three "flavors" to another.
The UMD research going on at Minnesota’s Soudan Underground Laboratory is a continuation of this study. Habig came to UMD from Boston to UMD in 2000 to head up the cutting-edge physics experiments. Habig and his Minnesota team are working to take those conclusions to the next step at the neutrino detector in the Soudan lab and now at a second underground detector near the Ash River, 30 miles southeast of International Falls. They're studying neutrinos fired underground, directly from the Fermi National Accelerator Laboratory near Chicago.
Written by Cheryl Reitan, October 2015.
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