Constraints for stellar electron-capture rates on ${}^{86}$Kr via the ${}^{86}$Kr($t$,${}^3$He$+\gamma$)${}^{86}$Br reaction and the implications for core-collapse supernovae

Abstract

In the late stages of stellar core-collapse, prior to core bounce, electron captures on medium-heavy nuclei drive deleptonization and simulations require the use of accurate reaction rates. Nuclei with neutron number near $N=50$, just above atomic number $Z=28$, play an important role, but rates used in astrophysical simulations rely primarily on a relatively simple single-state approximation. In order to improve the accuracy of astrophysical simulations, experimental data are needed to test the electron-capture rates and to guide the development of better theoretical models. This work presents the results of the ${}^{86}$Kr($t$,${}^3$He+$\gamma$) experiment at the NSCL, from which an upper limit for the Gamow-Teller strength up to an excitation energy in ${}^{86}$Br of 5 MeV is extracted. The derived upper limit for the electron-capture rate on ${}^{86}$Kr indicates that the rate estimated through the single-state approximation is too high and that rates based on Gamow-Teller strengths estimated in shell-model and QRPA calculations are more accurate. The QRPA calculations tested in this manner were used for estimating the electron capture rates for 78 isotopes near $N=50$ and above $Z=28$. The impact of using these new electron-capture rates in simulations of supernovae instead of the rates based on the single-state approximation is investigated, indicating a significant reduction in the deleptonization that affects multi-messenger signals, such as the emission of neutrinos and gravitational waves.

arXiv comment15 pages, 10 figures

References in corpus (33)

• How Massive Single Stars End their Life
• Theory of Core-Collapse Supernovae
• Core-collapse supernova equations of state based on neutron star observations
• Quantum Monte Carlo Calculations of Light Nuclei
• Shell-model calculations of stellar weak interaction rates: II. Weak rates for nuclei in the mass range A=45-65 in supernovae environment
• Mass Limits For Black Hole Formation
• Nuclear weak-interaction processes in stars
• Perspectives on Core-Collapse Supernova Theory
• A New Open-Source Code for Spherically-Symmetric Stellar Collapse to Neutron Stars and Black Holes
• Electron capture rates on nuclei and implications for stellar core collapse
• The effective g_A in the pf-shell
• Beta decay of r-process waiting-point nuclei in a self-consistent approach
• The consequences of nuclear electron capture in core collapse supernovae
• An Open-Source Neutrino Radiation Hydrodynamics Code for Core-Collapse Supernovae
• New T=1 effective interactions for the f5/2 p3/2 p1/2 g9/2 model space; Implications for valence-mirror symmetry and seniority isomers
• Equation of State Effects on Gravitational Waves from Rotating Core Collapse
• Finite amplitude method for the quasi-particle-random-phase approximation
• Global description of beta-minus decay in even-even nuclei with the axially-deformed Skyrme finite amplitude method
• The (t,3He) and (3He,t) reactions as probes of Gamow-Teller strength
• GT strengths and electron-capture rates for pf-shell nuclei of relevance for late stellar evolution
• Estimates of Stellar Weak Interaction Rates for Nuclei in the Mass Range A=65-80
• Unblocking of the Gamow-Teller strength in stellar electron capture on neutron-rich Germanium isotopes
• The Sensitivity of Core-Collapse Supernovae to Nuclear Electron Capture
• On the extraction of weak transition strengths via the (3He,t) reaction at 420 MeV
• Electron capture and beta-decay rates for sd-shell nuclei in stellar environments relevant to high density O-Ne-Mg cores
• Finite Amplitude Method for Charge-Changing Transitions in Axially-Deformed Nuclei
• Gamow-Teller Strength in the Region of ${}^{100}$Sn
• Comparing treatments of weak reactions with nuclei in simulations of core-collapse supernovae
• Beta decay of deformed r-process nuclei near A = 80 and A= 160, including odd-A and odd-odd nuclei, with the Skyrme finite-amplitude method
• Gamow-Teller Unit Cross Sections for (t,3He) and (3He,t) Reactions
• Dependence of weak interaction rates on the nuclear composition during stellar core collapse
• Stellar electron capture rates on neutron-rich nuclei and their impact on core-collapse
• Experimental Constraint on Stellar Electron-Capture Rates from the ${}^{88}\text{Sr}(t,{}^3\text{He}+\gamma ){}^{88}\text{Rb}$ reaction at 115 MeV/u

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• Impact of electron capture rates on nuclei far from stability on core-collapse supernovae
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• Comparison of Electron Capture Rates in the N=50 Region using 1D Simulations of Core-collapse Supernovae