Description of ${}^{93}$Nb stellar electron-capture rates by the Projected Shell Model

Abstract

Capture of electrons by nuclei is an important process in stellar environments where excited nuclear states are thermally populated. However, accurate treatment for excited configurations in electron capture (EC) rates has been an unsolved problem for medium-heavy and heavy nuclei. In this work, we take the ${}^{93}$Nb $\to$ ${}^{93}$Zr EC rates as the example to introduce the Projected-Shell-Model (PSM) in which excited configurations are explicitly included as multi-quasiparticle states. Applying the prevalent assumption that the parent nucleus always stays in its ground state in stellar conditions, we critically compare the obtained PSM results with the recently-measured Gamow-Teller transition data, and with the previous calculations by the conventional shell model and the quasiparticle random-phase approximation. We discuss important ingredients that are required in theoretical models used for stellar EC calculations, and demonstrate effects of the explicit inclusion of excited nuclear states in EC rate calculations, especially when both electron density and environment temperature are high.

References in corpus (10)

• Theory of Core-Collapse Supernovae
• Measurement of the Weak Axial-Vector Coupling Constant in the Decay of Free Neutrons Using a Pulsed Cold Neutron Beam
• Stellar electron-capture rates calculated with the finite-temperature relativistic random-phase approximation
• Electron capture in stars
• Stellar electron-capture rates in pf-shell nuclei from quasiparticle random-phase approximation calculations
• Modification of the Brink-Axel Hypothesis for High Temperature Nuclear Weak Interactions
• Toward extremes of angular momentum: Application of the Pfaffian algorithm in realistic calculations
• Shell model method for Gamow-Teller Transitions in heavy, deformed nuclei
• Gamow-Teller strength for the analog transitions to the first T=1/2, J^pi=3/2- states in 13C and 13N and the implications for Type Ia supernovae
• Urca Cooling in Neutron Star Crusts and Oceans: Effects of Nuclear Excitations

Cited by in corpus (1)

• An effective and efficient algorithm for the Wigner rotation matrix at high angular momenta