April 1, 2017 at 11:15 pm

INPP Seminar | The Sensitivity of Core-Collapse Supernovae to Nuclear Electron, April 4

The Institute of Nuclear and Particle Physics (INPP) presents Chris Sullivan, of Michigan State University, on “The Sensitivity of Core-Collapse Supernovae to Nuclear Electron” on Tuesday, April 4, at at 4 p.m. in Edwards Accelerator Lab, Roger W. Finlay Conference Room.

Chris Sullivan

Chris Sullivan

Abstract: Recently, the sensitivity of the core-collapse and early post-bounce phases of core-collapse supernovae (CCSNe) to nuclear electron-capture (EC) was examined. In this study, EC rates were adjusted by factors consistent with uncertainties indicated by comparing theoretical rates to those deduced from charge-exchange and β-decay measurements. To ensure a model-independent assessment, sensitivity studies across a comprehensive set of progenitors and equations of state were performed. Variations of the protoneutron star inner-core mass and peak electron-neutrino luminosities were observed to be 5 times larger when varying the EC rates than what is observed when fixing the rates and utilizing a wide array of progenitor models. Furthermore, the simulations were found to be particularly sensitive to the reduction in rates for
neutron-rich nuclei near the N = 50 closed neutron shell. As measurements for medium-heavy (A>65) and neutron-rich nuclei are sparse, and because accurate theoretical models that account for nuclear structure considerations of individual nuclei are not readily available, rates for these species are likely overestimated. In this talk, I will describe the impact this overestimate may have to the core-collapse trajectory, the detailed sensitivity of the core-collapse and bounce phases of
CCSNe to EC rates, and I will suggest specific areas of focus for future experimental and theoretical efforts.

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