Physics Prof. Recipient of 2023 Vogt Medal
Physics professor Dr. Paul Garrett was recently the recipient of the Vogt medal, a prestigious Canadian national award for significant contributions to the field of subatomic physics. The award is presented annually by TRIUMF and the Canada Association of Physicists (CAP) and recognizes excellence in subatomic physics research based in Canada. With a successful career in subatomic physics, Garrett’s work has garnered international recognition. His most recent contributions could change our understanding of the structure of atomic nuclei and impact how the elements are created that make up our universe.
Discovering Inconsistencies in Nuclear Theory
Garrett’s award-winning research is focused on the structure of atomic nuclei – how the protons and neutrons that make up atoms are arranged. His team conducts experiments at large scale facilities worldwide in order to probe nuclear structure through excitations that are `cooperative’ in their makeup. “Think of these excitations like “the wave” you sometimes see in a sports stadium,” explains Garrett. “Everyone on their own is doing their own thing, but together you have this collective behaviour.” These cooperative – or collective – nuclear excitations can impact the shape of atomic nuclei.
Since the 1950’s, a theory that describes these collective nuclear excitations has been well accepted, but Garrett’s team began noticing discrepancies in their experimental data. “We began seeing deviations from the expected theory that always followed the same pattern,” says Garrett. “It wasn’t random.” The current theory assumes that many nuclei have a spherical shape that undergo collective excitations that are vibrations of the nuclear surface. However, Garrett’s findings suggest that this is not an accurate picture. Instead, nuclei that appear to have a pattern of excitations expected for spherical shapes are actually deformed into shapes like a football or a M&M candy that rotate as they undergo excitation. This distinction has important implications on our current understanding of nuclear structure, and may impact the abundance of elements that make up our universe.
The scientific community was resistant to accept the new findings and the implications they would have. However, the resistance only challenged Garrett and his collaborators to work harder, performing experiments with more-and-more sensitivity to collect deeper information to create a more complete picture. In 2019, more than 15 years after the first signs of discrepancies were observed, Garrett and his team published their results from an experiment at TRIUMF that provided very convincing evidence in favour of a new theory.
A New Picture of Atomic Nuclei
This experiment, and the implications it has on our current understanding of nuclear structure, lead to Garrett’s nomination for the Vogt medal. Garrett acknowledges the contributions of many collaborators on this achievement with thanks. “It was 10 years in the making, and there’s a long list of close collaborators who worked on this.”
Garrett is now spearheading an international effort to further test the new theory of atomic nuclei. Several international labs, including three in Europe, one in the US, and TRIUMF in Canada, are involved. Garrett is currently seeking enthusiastic and passionate students to join his team.
More information, including a link to the original article, can be found at https://physics.aps.org/articles/v12/s113, https://www.nature.com/articles/d41586-019-03006-4, and https://www.nature.com/articles/s41567-019-0719-x.