When the Virginia Tech Board of Visitors bestowed the title of Alumni Distinguished Professor on longtime Virginia Tech College of Science physicist Leo Piilonen earlier this month, he was in Tsukuba Science City, Japan, working on the high-energy particle physics detector Belle II.

Piilonen’s visit to Japan to the High Energy Accelerator Research Organization in Tsukuba to perform maintenance and make improvements to Belle II’s KLM subsystem is indicative of his service to science. His recent trip to Japan, accompanied by a postdoctoral researcher and a graduate student, also included a bullet train journey to Nagoya University for the weeklong Belle II collaboration meeting, where the three gave presentations.

The Alumni Distinguished Professor title is a preeminent appointment recognizing faculty members who demonstrate extraordinary accomplishments and academic citizenship through substantive scholarly contributions across all three of the university’s core mission areas of teaching, research or creative activity, and engagement.

Piilonen has enjoyed a successful career an educator and as a scientist experimenting with high-energy particle physics detectors. He and a long list of collaborators over the years helped design and build the outermost component, the KLM, of the original Belle and the new Belle II detectors during the 1990s, with a major 2012 overhaul for the former. Belle II, in particular, was designed to make precise measurements of weak interaction parameters and find “new physics” beyond the standard model of known particle physics. The measurements carried out in Japan helped earn a 2008 Nobel Prize in Physics. 

Piilonen has served as the elected co-leader of the 500-member Belle Collaboration as well as the elected chair of the Belle II Collaboration’s Institutional Board, which represents the interests of its 1,000 members. In 2016, Piilonen led a local team to create a virtual reality interactive model of the Belle II experiment, partly supported by the Virginia Tech Institute for Creativity, Arts, and Technology. The effort was designed to bring particle physics research into the classroom and has thus far been adopted by more than 30 institutions worldwide for student training and public outreach, according to Piilonen.

Piilonen has received continuous funding from the U.S. Department of Energy since 1988, with a career funding total of $13.6 million. He has supervised 21 Ph.D. students and 12 postdoctoral associates.

The honor follows the American Association for the Advancement of Science’s election of Piilonen, professor in the Department of Physics, to its 2021 fellowship class. The association honored him for his “distinguished contributions to experimental elementary particle physics, particularly for leadership in the Belle and Belle II collaborations and in their muon and K-long meson detection and identification.”

He is also a fellow of the American Physical Society and held the William E. Hassinger, Jr. Senior Fellowship in Physics at Virginia Tech from 2010-16. Other honors include a 2019 Outstanding Faculty Award from the State Council of Higher Education for Virginia and a 2019 Alumni Award for Excellence in Research from Virginia Tech.

"The Alumni Distinguished Professor appointment for Leo is richly deserved,” said Mark Pitt, professor and chair of the Department of Physics. “Throughout his career here, he has made extraordinary contributions in all three responsibility areas of a faculty member — research, teaching, and engagement."

Piilonen joined Virginia Tech in 1987 and became the first director of the department’s Center for Neutrino Physics in 2010. He then served as department chair from 2012-15. He earned a bachelor's degree in physics from the University of Toronto in 1978 and a Ph.D., also in physics, from Princeton University in 1985. Before coming to Virginia Tech, Piilonen was a postdoctoral fellow at the Los Alamos National Laboratory. All this followed Piilonen’s childhood in a small Canadian village with a one-room log cabin schoolhouse until he was in junior high.

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