February 1, 2020 at 7:45 pm

INPP Seminar | Constraining Electron-capture Rates in Core-collapse Supernovae through Charge-exchange Reactions, Feb. 18

The Institute of Nuclear and Particle Physics (INPP) presents Remco Zegers of MSU, on “Constraining Electron-capture Rates in Core-collapse Supernovae through Charge-exchange Reactions”, on Tuesday, Feb. 18, at 4 p.m. in Edwards Accelerator Lab, Roger W. Finlay Conference Room.

Photo of Remco Zegers

Remco Zegers

Abstract: Electron captures on medium-heavy nuclei play an important role in the late stages of the evolution of core-collapse supernovae, just prior to the explosion. In particular, nuclei around neutron number N=50, just above nickel-78, have been identified as especially important for the deleptonization of the star’s core. The astrophysical simulations of these cataclysmic events require accurate electron-capture rates. One has to largely rely on theoretical models, which must be benchmarked and guided by experimental data. This work describes a broad effort to improve the electron capture-rates for nuclear astrophysical simulations, focusing on nuclei near N=50. To benchmark the theoretical data, Gamow-Teller strengths obtained from charge-exchange experiments are key. Recently, several (t,3He+g) charge-exchange experiments on nuclei at or near N=50 have been completed that guide the theory.  In addition, an electron-capture rate library has created that astrophysicists can use in their simulations and that contains a wide variety of rate sets based on different models. Experimental data also serves to estimate the uncertainties in these rates, which has been very helpful for sensitivity studies of core-collapse supernovae and their multi-messenger signals to electron-capture rates by using one-dimensional core-collapse simulations.

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