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# Physics and Astronomy Defense – Evan Ney

## November 8, 2021 @ 10:00 am - 12:00 pm

**UNC-CH Physics and Astronomy Defense
**

*Evan Ney
*

**“Towards a complete theory of beta decay in density functional theory”**

The origin of the heavy elements through the rapid neutron capture process (r-process) remains an active area of theoretical and experimental research. This interdisciplinary effort requires a combination of reliable nuclear data and realistic astrophysical simulations. Most nuclei involved in the r-process are too unstable to be produced in a laboratory and contain too many degrees of freedom to be computationally tractable for ab-initio nuclear theory. However, nuclear density functional theory (DFT) is one of the few approaches which allow for self-consistent, microscopic calculations of properties in every nucleus.

The dynamics of the r-process and the produced elemental abundances are largely determined by beta- decay half-lives. In this dissertation I present results from several novel calculations that constrain beta-decay half-lives in a diverse range of nuclear systems. These include (i) a calculation of electron-capture rates in hot stellar environments, (ii) a global calculation of beta-minus-decay half-lives in all neutron-rich nuclei where odd particle numbers are treated consistently, and (iii) a study of the effects of two-body weak currents on Gamow-Teller transitions. I evaluate these modern calculations and discuss their implications for r-process nucleosynthesis.

*This defense will be in-person as well as held remotely via Zoom: https://unc.zoom.us/j/92560571618?pwd=U3IwYXNGU0M5TGNFVzQ2dTNobmtUZz09 *