09/20/2024
By Amanda Vozzo
Time: 4 to 5 p.m.
Location: Ball Hall 214
Speaker: Peter Bender, Assistant Professor, Department of Physics and Applied Physics, University of Massachusetts Lowell
Title: “Nuclear Structure through Gamma-Ray Spectroscopy: Insights from the Island of Inversion”
Abstract: Nuclear science fundamentally explores the formation of protons and neutrons from elementary particles and the interactions between them. One successful model describing this is the nuclear shell model, which treats nucleons as valence particles within a mean-field. Initially, this model was developed for nuclei near stability, where so-called ‘magic numbers’ — benchmarks defining the nuclear potential — are well understood. However, for more exotic neutron-rich nuclei, these magic numbers often break down. A prominent region where this breakdown occurs is in neutron-rich nuclei with neutron number N=20. In this mass region, nucleons compete to occupy orbitals between shells, resulting in an inversion of the expected configuration observed near stability. This region, referred to as the "island of inversion," has played a significant role in advancing our understanding of nuclear structure. In this presentation, I will discuss the physics of exotic isotopes in the "island of inversion" and highlight recent experimental efforts, focusing on γ-ray spectroscopy, to explore this area of the nuclear chart. I will emphasize the role of spectroscopic techniques to clearly identifying key nuclear states, determining spin and parity assignments from the detection of deexciting γ-rays observed following nuclear reactions or decays. These identified states are essential to refining our understanding of the underlying nuclear potential – a potential essential to understand the smallest scales of the universe, such as subatomic particles, to the largest, like stars.
Bio: Peter Bender is an Assistant Professor in the Department of Physics & Applied Physics at the University of Massachusetts Lowell. He earned his BS in Physics from North Georgia College and State University, and both his MS and PhD in Experimental Nuclear Physics from Florida State University. Before joining UML, he held key roles in the low-energy nuclear physics community, overseeing large HPGe spectrometers such as TIGRESS at TRIUMF and GRETINA at the NSCL. He is a specialist in high-resolution γ-ray spectroscopy and conducts independent, funded research in both applied and fundamental nuclear science at UML.