Speaker to focus on DUNE, Davis connection

Fifty years ago, Ray Davis Jr. announced his initial findings from his Solar Neutrino Experiment at the Homestake Gold Mine in Lead, South Dakota. The results were perplexing: Davis had detected only one-third of the neutrinos he expected to find. “Nothing was wrong with the experiments,” Davis explained in his 2002 Nobel Prize lecture, “something was wrong with the neutrinos.”

This year, during Sanford Lab’s Neutrino Day, we celebrate Davis’ scientific discovery. His research opened new windows into the mysteries of the universe, allowing modern-day scientists to extract secrets from cosmic phenomenon today. The discovery of solar neutrinos proved that nuclear fusion is the energy source of the sun and gave birth to a new field of science: neutrino physics.

“Ray Davis’ work moved the field from understanding neutrinos to what neutrinos can tell us about the whole universe,” said Bonnie Fleming, deputy chief research officer at Fermilab. “His was one of the first experiments to detect solar neutrinos and to observe a deficit of neutrinos coming from the sun in the process. This deficit, known at the time as the ‘Solar Neutrino Deficit,’ was a first indication that neutrinos oscillate and therefore have mass, which is very important.”

Fleming will give a presentation Saturday, July 8, during this year’s Neutrino Day. She will discuss how important scientific discovery is and in particular, how Davis’ work has contributed to scientific research today. Her presentation will be held at 11 a.m. in the Historic Homestake Opera House.

Davis’ experiment appeared flawed because, as it turned out, neutrinos change types, or flavors, as they travel: from electron to muon to tau (in no particular order). Davis’ experiment detected only one neutrino: the electron.

The Deep Underground Neutrino Experiment (DUNE), a Department of Energy-funded experiment led by Fermilab, hopes to further unravel the secrets of neutrinos. DUNE could help us understand the role neutrinos play in the universe, how and why they oscillate, and, perhaps, catch a glimpse of the birth of black hole.

Without realizing it, Davis’ observed neutrino oscillations with his solar neutrino experiment. “DUNE will characterize these oscillations to look for clues in understanding our matter dominated universe,” Fleming said.

And that leads to other questions. Do neutrinos oscillate at the same rate as anti-neutrinos or do they behave differently? If they do behave differently, is it a clue to differences between matter and anti-matter?

“We could find the reason for why we live in a matter dominated universe—and why we exist at all,” said Fleming. “This is what the DUNE experiment will address.”