Physicists dig deep to seek the origin of matter

Abstract

“Here’s to low-grade ore and plenty of it,” mining magnate George Hearst reportedly said after he bought the Homestake Gold Mine in Lead, SD, in June 1877. Although the mine contained less than an ounce of the precious metal per ton, the sheer quantity of ore meant that the operation was profitable (1). From 1876 to 2001, miners dug thousands of feet in search of gold, making Homestake the largest and deepest gold mine in North America. Now, physicists and engineers are excavating gigantic caverns inside the defunct mine to look for something even more elusive: neutrinos. New caverns being excavated inside the defunct Homestake Gold Mine in Lead, SD, will house DUNE. The world’s largest such detector, DUNE will start running in 2026. Image credit: Shutterstock/Tom Grundy. The new caverns will house the Deep Underground Neutrino Experiment (DUNE), the world’s largest such detector. DUNE will start running in 2026, studying an intense beam of neutrinos coming from Fermilab, near Batavia, IL, about 1,300 kilometers away. The experiment will focus on a profound question: what is the origin of matter? In the early universe, matter and antimatter should have formed in equal amounts and then annihilated each other to leave only radiation. But the observable universe with its galaxies, stars, and planets is made of matter, so clearly, not all of it was annihilated. “How did we get from a universe that was equal amounts of matter and antimatter to a universe where there’s a bit of matter left over?” asks neutrino physicist Deborah Harris of Fermilab. Neutrinos could be key to answering that question. Because of their special ability to transform from one type into another, they may reveal fundamental differences between matter and antimatter. Homestake has history with the neutrino, offering up the first signs of this particle’s …