Adrian Melissinos remembered as a pathbreaking particle physicist, mentor

August 5, 2022

Adrian Melissinos, a professor of physics at the University of Rochester from 1955 to 2022, is being remembered for his significant contributions in the search for dark matter and his skill as a mentor to generations of graduate students. Melissinos died in July at the age of 92.

"To me, Adrian was a physicist's physicist," says Steve Manly, professor of physics at Rochester. "He was a smart and creative individual presence in a world where the science of particle physics became more and more programmatic. He found joy in doing physics in a way that few of us manage to do."

Melissinos was born in Thessalonkiki, Greece, and graduated from the Greek Royal Naval Academy in 1948. He served in the Hellenic Navy, and, in 1955, began graduate studies at the Massachusetts Institute of Technology, where he earned his PhD in physics in 1958. He joined the Rochester faculty later that year.

Examining the nature of the universe

During his long career at Rochester, Melissinos developed an international reputation for his research in experimental high-energy physics and the nature of the universe, including unravelling the mystery of dark matter. Scientists have attempted for decades to understand and detect dark matter, which accounts for about 85 percent of all matter in the universe. However, researchers have so far only inferred dark matter indirectly by observing gravitational effects that cannot be explained by standard theories of gravity. Proof of dark matter particles would fundamentally change our understanding of the makeup of the universe.

In the 1980s, Melissinos was involved in the first searches for cosmic axions-hypothetical, very light subatomic particles that barely interact with normal matter. Scientists conjecture that axions could be one component of dark matter. The series of experiments on axions that Melissinos led at Brookhaven National Laboratory in the early 1990s was, at the time, one of the most exhaustive searches ever for dark matter and helped physicists narrow down the properties that the hypothetical particles could have.

"This type of search is perhaps Adrian's greatest contribution to the search for the unknown," says Kirk McDonald, a professor emeritus of physics at Princeton University.

Scientists conjecture that axions could be one component of dark matter. The series of experiments on axions that Melissinos led at Brookhaven National Laboratory in the early 1990s was, at the time, one of the most exhaustive searches ever for dark matter and helped physicists narrow down the properties that the hypothetical particles could have.

In the late 1990s, Melissinos and McDonald were members of a team of 20 physicists at Stanford Linear Accelerator Center (SLAC) who studied interactions between high-powered lasers and electrons. The team's experiments involved colliding high-energy electrons produced by SLAC's two-mile-long accelerator and photons from a powerful "tabletop terawatt" glass laser developed at Rochester's Laboratory for Laser Energetics. In 1997, the team made headlines around the world when their experiments provided evidence, for the first time, of creating particles of matter from light.

Melissinos's experimentation and search for axions were "his passion until the very end," says his friend and colleague Ashok Das, a professor of physics at Rochester. "Just prior to his passing away, Adrian discussed a physics question about axions with me over lunch and ended up sending me a draft of a paper a week or so later for my comments. He was already well past 90 and such was his dedication to understanding questions in physics."

As experiments in particle physics grew in scale and became "more mechanized with complicated computer codes," Das continues, "Adrian stuck to his roots and only did small-scale experiments where he had more control and more understanding of what was going on. He wanted to understand complicated physics questions in a rational and physical way through what was already known."

To explain his devotion to his work, Melissinos told the Rochester Review in 1999, simply, "I love the joy of discovery, and of sharing that discovery with others."

An inspiring mentor and colleague

In addition to his research, Melissinos mentored 31 PhD students during his tenure at Rochester. These students included Michael Fitch '01 (PhD), who, in 2001, received the Universities Research Administration's (URA) honor for the best doctoral thesis work done at Fermi National Laboratory. Under Melissinos's tutelage, Fitch developed, as part of his thesis, a new technique for positioning the beam of particles for future particle accelerators.

"Adrian was a huge influence on me, and I grew tremendously under his supervision," says Fitch, now a researcher at the John Hopkins Applied Physics Laboratory. "With my own ideas, Adrian would have me write them up, do the calculations, and find any flaws in the logic or design-an incredibly useful exercise in sharpening and refining ideas. His boundless energy, his charm, his enthusiasm, and his zeal for teaching have inspired me to this day."

A prolific writer, Melissinos was the author or co-author of more than 200 journal publications and of four textbooks and several monographs. His book Experiments in Modern Physics is a standard textbook used in undergraduate and graduate laboratory physics courses around the world.

In addition to his work at SLAC and Brookhaven National Laboratory, Melissinos was involved in research with CERN and Fermilab. He was a visiting professor at the University of Athens and a visitor at DESY, a research center in Germany. He served on many national and international organizations and advisory panels, including as chairman of the Brookhaven National Laboratory visiting committee and the SLAC Scientific Policy committee. He also served as a member of the American Physical Society Council. He was named a Fellow of the American Physical Society in 1965 and was a corresponding member of the National Academy of Athens.

Melissinos was predeceased by his wife of 50 years, Joyce, and his son, John. He is survived by his son, Andrew; daughter-in-law, Candice Culnane, and granddaughters, Chesney and Logan Melissinos; and many other relatives and family members in the US, Greece, Switzerland, Italy, and Australia.

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Tags: Adrian Melissinos, Arts and Sciences, dark matter, Department of Physics and Astronomy

Category: University News

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