Physicists are delving into the mysteries of the universe’s origins by studying one of its smallest components: neutrinos. These nearly massless particles, which travel at close to the speed of light and pass through matter by the trillions every second, could hold the key to understanding why the universe exists as it does today.
Professor Alexandre Sousa from the University of Cincinnati has been at the forefront of this exploration, contributing to a new white paper in Journal of Physics G that outlines the next decade of neutrino research. The study aims to solve anomalies observed in experiments, such as the possible existence of a fourth neutrino flavor, known as the sterile neutrino. Unlike the three known neutrino “flavors,” this theoretical particle appears to interact only with gravity, evading the other fundamental forces.
A significant focus of neutrino research is unraveling why the universe contains more matter than antimatter, despite theoretical models suggesting the Big Bang should have produced them in equal quantities. “Neutrinos seem to hold the key to answering these very deep questions,” Sousa explained.
Sousa is part of the Deep Underground Neutrino Experiment (DUNE), a global collaboration led by Fermilab. This ambitious project is designed to create and study the most powerful neutrino beam ever generated, with detectors placed 5,000 feet underground in a former gold mine in South Dakota. Shielded from cosmic rays and background radiation, these detectors aim to isolate particles generated during experiments, providing unprecedented data.
“DUNE will be the best neutrino experiment ever,” Sousa said, highlighting the potential for groundbreaking discoveries when it becomes operational in the coming years.
The research described in the white paper involved more than 170 contributors from 118 institutions worldwide, emphasizing the scale and collaborative nature of modern particle physics. “It was a great example of collaboration among a diverse group of scientists,” Sousa noted.
Meanwhile, Sousa and UC Associate Professor Adam Aurisano are participating in another Fermilab project, NOvA, which examines how neutrinos change flavors. Their recent findings provided the most precise measurements of neutrino mass to date, advancing understanding in the field.
In Japan, the Hyper-Kamiokande (Hyper-K) observatory is under construction, promising complementary insights alongside DUNE. The combination of these experiments is expected to yield significant answers to unresolved questions about neutrino behavior and their role in shaping the universe.
As the DUNE and Hyper-K experiments progress, physicists anticipate major discoveries in the 2030s. “These experiments combined will advance our knowledge immensely,” Sousa said.
While the study of neutrinos might not impact daily life directly, the quest to understand these particles represents a fundamental effort to answer humanity’s oldest question: why does the universe exist as it does?
