Martha Constantinou, associate professor of physics and vice chair of department of physics at Temple University, will be the keynote speaker during the 12th annual Losoncy Lecture Series.
WYOMISSING, Pa. — The 12th annual Penn State Berks Losoncy Lecture in Physics and Astronomy will be presented by Martha Constantinou, associate professor of physics and vice chair of department of physics at Temple University. Constantinou will present “Unlocking the Secrets of the Proton’s Spin: Insights from Simulations of the Core of Visible Matter” on Wednesday, April 9, 2025. A reception will begin at 4 p.m. in the college’s Perkins Student Center Multipurpose Room and the lecture begins at 4:45 p.m. in the Perkins Student Center Auditorium. This event is free and open to the public.
The lecture series is named in honor of George J. Losoncy, a retired Penn State Berks maintenance employee who donated $50,000 to establish a research endowment in physics and astronomy at Penn State Berks.
According to Constantinou: Over 99% of the mass in visible matter is concentrated within atomic nuclei, which are composed of bound states of quarks and gluons (collectively called partons). The partons represent the fundamental degrees of freedom in quantum chromodynamics (QCD), the theory governing the strong nuclear force, one of four fundamental forces in nature for the visible matter. More than half a century ago, deep-inelastic electron-proton scattering experiments revealed that protons have a rich internal structure, challenging our classical picture of elementary particles.
One of the most discussed mysteries in this field is the proton spin puzzle: how the intrinsic spin of the proton arises from the contributions of its quark and gluon constituents. Early models suggested that quarks carry most of the proton’s spin, however experiments soon showed that their contribution was unexpectedly small. This discovery sparked a decades-long effort to understand the missing components of proton spin. Due to QCD's highly nonlinear nature, solving this problem requires a computational approach that goes beyond perturbative techniques. Lattice QCD provides a first-principles framework by discretizing spacetime into a four-dimensional grid, enabling large-scale numerical simulations of quark and gluon interactions. In recent years, state-of-the-art simulations with physical quark masses have provided unprecedented insights into hadron structure.
In this talk, Constantinou will explore how lattice QCD is being used to shed new light on the proton spin decomposition, focusing on the contributions from quarks, gluons, and orbital angular momentum. She will also discuss recent breakthroughs in evaluating the gluon spin component, a crucial missing piece in solving the proton spin puzzle. These efforts not only deepen understanding of QCD but also have far-reaching implications for future experiments at facilities such as the Electron-Ion Collider.
Constantinou is a recipient of the prestigious U.S. Department of Energy Early Career Award. She earned her doctoral degree in theoretical computational physics and her baccalaureate degree in physics, both from the University of Cyprus.
For more information, contact Leonard Gamberg, professor of physics, at LPG10@psu.edu.
Leonard Gamberg
Dr. Leonard Gamberg, Professor of Physics at Penn State Berks
