A two-day celebration this weekend honors a University of Rochester physicist known for following his curiosity to diverge from traditional scientific paths---and making a heap of discoveries in the process.
More than 125 physicists and other colleagues will attend the symposium on "Probing Luminous and Dark Matter" Friday and Saturday at the Hyatt Regency Hotel in downtown Rochester. The celebration is in honor of Adrian Melissinos, professor of physics, who turned 70 this summer. Nobel laureate Leon Lederman, who has worked closely with Melissinos, is among the physicists from around the world who will discuss future directions in particle physics. Presentations will cover an array of topics, including cosmic rays, gravity, lasers, collider physics, and an array of exotic or suspected particles such as neutrinos, muons, and axions.
Born in Thessaloniki, Greece, Melissinos attended the Greek naval academy and then joined the Royal Hellenic Navy in 1948, serving first as an ensign and then lieutenant, where among other duties he commanded a mine sweeper and occasionally visited the United States picking up new ships for the Greek navy. Melissinos had maintained a strong interest in physics since his days as a student, and during a trip to Boston, he visited the Massachusetts Institute of Technology and decided to apply to MIT's graduate physics program. When his tour of duty was up, he left the Greek navy and attended MIT, where he earned his master's degree in 1956 and his Ph.D. in 1958. He immediately joined the University of Rochester, where he has studied a gamut of questions about the nature of the universe.
"Adrian is as close to a Renaissance particle physicist as I know," says longtime colleague Thomas Ferbel, professor of physics. "He has a broad range of interests. Some of us keep repeating our thesis for the rest of our lives; Adrian is not like that. He goes out and constantly looks into new areas, with the right combination of technical skill and intuition to make a go of it. He combines mathematical strength and physical insight and pulls tools from different fields to probe in new directions. He'll take a different approach, and it will start a whole new field.
"When a new idea comes along, a physicist like Enrico Fermi might first calculate everything possible to the Nth degree, thoroughly checking for errors before starting an experiment. When Adrian becomes enamored with an idea, he rushes in, and he usually succeeds," adds Ferbel. "Enthusiasm and imagination have marked Adrian's work for decades."
The view is shared by physicist Paul Slattery, who has worked with Melissinos for 30 years. "Adrian's contagious enthusiasm for physics is backed up by a keen intelligence and seemingly boundless energy which have permitted him to quickly master new technologies and then almost immediately employ these techniques to explore nature in daring and imaginative ways."
During his four decades at the University, Melissinos has used all of the world's most powerful particle accelerators, including those at Fermilab, Brookhaven National Laboratory, CERN and DESY in Europe, and Cornell and Stanford universities. Using such conventional equipment, Melissinos often goes on a search for the exotic. Earlier this decade Melissinos headed a team of physicists in one of the most extensive hunts yet for "axions." Physicists can account for only a small fraction of the material that their theories say must exist in the universe, so the hunt is on for the rest, "the missing mass" that has managed to avoid physicists' prying eyes. Candidates for the missing mass include WIMPS (weakly interacting massive particles), heavy neutrinos, brown dwarfs (failed stars that don't burn brightly enough to be seen from Earth), and axions, very light particles that barely interact with normal matter. The series of experiments on axions that Melissinos led at Brookhaven National Laboratory on Long Island was one of the most exhaustive searches for dark matter and has helped physicists narrow down the properties that the hypothetical particles can have.
The accelerators Melissinos and colleagues use in such experiments typically are made up of a mind-boggling array of electronics that must perform reliably. Always amused by a mystery, 10 years ago Melissinos and other physicists at CERN in Switzerland were puzzled by slight but unexpected fluctuations in the energy readings of some of that accelerator's equipment. Melissinos helped determine that the moon's gravity was having an ever-so-slight effect on the accelerator, shifting it just enough to change the accelerator's properties from moment to moment.
More recently, Melissinos earned headlines around the world for the results of an innovative experiment where his team brought together high-energy electrons traveling near the speed of light, produced by Stanford's two-mile-long accelerator, and photons from a powerful "tabletop terawatt" glass laser developed at Rochester's Laboratory for Laser Energetics. By dumping an incredible amount of power---nearly as much as it takes to run the entire nation but lasting only a tiny fraction of a second---into an area less than one billionth of a square centimeter, the team created particles of matter from pure light.
To explain his fascination with such processes, Melissinos says simply, "I love the joy of discovery, and of sharing that discovery with others."
Melissinos is a fellow of the American Physical Society and the National Academy of Athens. He has been a visiting scientist at several laboratories and universities around the world and has more than 150 publications, along with four textbooks and several monographs, to his credit. His book on experimental physics has become a classic---a standard used in almost all undergraduate and graduate laboratory physics courses around the world. He worked together with University Professor Ashok Das on a textbook on quantum mechanics that also is used widely by students around the country. Says Das: "Adrian is always curious-he's not afraid to ask questions. This helps to make him a superb teacher and scientist, and is part of the reason students love him."