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Physics Colloquium: Constraining nuclear reaction networks relevant to the p-process

This is a past event.

Friday, October 18, 2019 at 1:30pm to 2:30pm

PG6 - Tech Station, 112
11200 SW 8th ST 33199, PG6 - Tech Station, Miami, Florida 33199

Orlando Gomez, Physics department, Notre Dame University

Abstract: Understanding the origin of the elements heavier than Iron continues to remain an active field of research in the 21st century. The majority of these elements are made through sequential neutron capture processes, the r- and s- process. A handful (~ 35) of proton-rich naturally occurring stable nuclei “p-nuclei” cannot be produced in this manner. How to accurately model and predict the observed abundances of the p-nuclei remains an open question. The currently most favored production mechanism is photodisintegration of intermediate and heavy elements at high temperatures (1 – 3 GK) in late evolution of massive stars.

However, well-known deficiencies in the current model is the underproduction of the Mo-Ru region as well with masses in the range of 150 - 167. A full time-dependent network calculation typically comprises several hundreds to thousands of nuclear reactions, many of which have not been experimentally measured and consequentially, have large uncertainties from the theoretical models that predict them.

In this talk, I will provide a brief overview of nucleosynthesis, the r-, s-, and p- process before focusing on the 102Pd(p,γ)103Ag,108Cd(p,γ )109In, and 110Cd(p,γ)111In reactions whose cross sections were measured at the University of Notre Dame in order to constrain theoretical model uncertainties. I will also present the High EffiCiency TOtal absoRption spectrometer (HECTOR) detector and γ-summing technique which was used to perform the measurement. Lastly, from our results, I will then discuss how we constrain the theoretical models and the resulting impact on the p-process network model.

Short Bio: Mr. Gomez is currently a 4th year PhD graduate student at the University of Notre Dame.  He received his B.S. in Physics at Florida International University with a minor in Astronomy in 2015. His current research interests are Nuclear Astrophysics and Machine Learning. Before his academic career, he served in the Florida National Guard for eight years as an infantry medic, including a year deployment to Iraq in 2009.

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