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A Crack in Nuclear Mirror Symmetry
Presented By: Daniel E.M. Hoff / Daniel_Hoff@uml.edu
Dan is currently a postdoctoral research associate at University of Massachusetts Lowell, joining shortly after finishing his PhD at Washington University in St. Louis under Dr. Lee Sobotka in 2018. He has worked on many different projects in his nuclear science career from searching for neutron-rich Hf K-isomers to studying isospin symmetry with beta-decay spectroscopy. He finds the nuclear landscape rich with systems to explore and his current research interests include nuclear reaction dynamics, nuclear structure, and nuclear astrophysics.
Abstract
Symmetries are ubiquitous in nature, and the observation of symmetry breaking often leads to new insights in physics. Within nuclear physics, it is possible to consider neutrons and protons as isospin projections of a single fermion. Nuclear states can then be characterized by a total isospin (or isobaric spin T) and this quantity is largely conserved in reactions and decays. A mirror symmetry emerges from this formalism; nuclei with exchanged numbers of neutrons and protons, or mirror nuclei, should have an identical set of states, including their ground state. Despite knowing that isospin symmetry is not perfect, it has proved to be rather robust across the chart of nuclides. In this talk, I will show evidence for mirror-symmetry violation in bound nuclear ground states between the mirror partners 73Sr and 73Br. By analyzing the beta-delayed proton emission of 73Sr, a spin assignment of Jπ = 5/2− is needed to explain the proton-emission pattern observed from the T= 3/2 isobaric-analog state in 73Rb, which is identical to the ground state of 73Sr. Therefore, the ground state of 73Sr must differ from its Jπ = 1/2− mirror 73Br. Download AbstractPresentation Slides
Oct 1, 2020
1:00 pm (CST)
Hosted By
Lawrence Berkeley National Laboratory