New Wright Lab director brings new insight into neutrinos

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This photograph shows the antineutrino detectors in one of the underground experimental halls. The three detectors are placed at a distance of about one mile from the nuclear reactor to measure the disappearance of neutrinos. (Photo by Daya Bay Group, University of Wisconsin)

When he came to Yale in July, Karsten Heeger was already a familiar figure in particle physics, especially for his work on low-energy neutrinos. As expected, the new director of Yale’s Wright Laboratory is already working to broaden and intensify the University’s research into some of the universe’s most mysterious components.

On Aug. 21 a major international experiment in which Heeger and his lab played a key role released fresh results about “the transformations of elusive, ghostlike neutrinos, particles that carry invaluable clues about the makeup of the early universe.”

The latest findings of the Daya Bay Collaboration, based in China, include the “the first data on how neutrino oscillation — in which neutrinos mix and change into other ‘flavors,’ or types, as they travel— varies with neutrino energy, allowing scientists to measure a key difference in neutrino masses known as ‘mass splitting,’” according to an announcement of the results.

The subtleties of neutrino oscillations and their other properties may help explain “some of the most mysterious questions about the universe,” according to the collaboration.

Heeger, who also is professor of physics at Yale, came from the University of Wisconsin. His research group will continue its work on reactor neutrinos, and he will coordinate the development of a research program on weak interactions and fundamental symmetries at Yale’s Wright Lab.

Within the Daya Bay Collaboration, Heeger’s group has been instrumental in the design, assembly, and installation of the antineutrino detectors for the reactor neutrino experiment. Members of the group have overseen the operation of its antineutrino detectors, and Heeger’s students and postdocs provided one of the independent analyses to identify the signal of neutrino oscillation and predict the neutrino flux from the Daya Bay reactors.

The experiment is based near the Daya Bay and Ling Ao nuclear power plants in China, northeast of Hong Kong.  The collaboration includes more than 200 scientists from six regions and countries.

Together, Heeger and fellow new Yale physics faculty member Reina Maruyama, assistant professor of physics, are adding new research efforts in the study of neutrinos and dark matter to the department’s portfolio.

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