Original e− Capture Cross Sections for Hot Stellar Interior Energies

Abstract

The nuclear electron capture reaction possesses a prominent position among other weak interaction processes occurring in explosive nucleosynthesis, especially at the late stages of evolution of massive stars. In this work, we perform exclusive calculations of absolute e−-capture cross sections using the proton–neutron (pn) quasi-particle random phase approximation. Thus, the results of this study can be used as predictions for experiments operating under the same conditions and in exploring the role of the e−-capture process in the stellar environment at the pre-supernova and supernova phase of a massive star. The main goal of our study is to provide detailed state-by-state calculations of original cross sections for the e−-capture on a set of isotopes around the iron group nuclei (28Si, 32S, 48Ti, 56Fe, 66Zn and 90Zr) that play a significant role in pre-supernova as well as in the core–collapse supernova phase in the energy range 0≤E≤50 MeV.

Feasibility study of nuclear excitation by electron capture using an electron beam ion trap

“…For most nuclei, their NEEC resonance cross sections are much larger than the direct photon absorption cross sections, which makes the NEEC to be a promising mechanism for effective nuclear excitation [17]. Just like the "electron captured on nuclei" process [19,20], the NEEC process, which is an "electron captured on atoms" process, play a significant role in the nucleosynthesis in astrophysical environments [21][22][23][24], such as in stars like the sun, nova, or supernova explosions.…”

Electron Capture on Nuclei in Stellar Environment

“…(where A denotes the mass number and Z the atomic number of the parent nucleus) and takes place in the hot stellar interior [1][2][3][4] is one of the essential processes that strongly influences the collapse of the inner core of massive stars, which finally leads to a type II supernova explosion [5][6][7][8].…”

“…Motivated by this effect, many authors emphasized the calculation of e − -capture rates based on the GT-type contributions (at momentum transfer q → 0) and evaluated them on the basis of the dominance of GT transitions [8,10,12,19,22,25]. In our previous work [7], by considering momentum-dependent operators, we saw that in addition to GT transitions, the Fermi (as well as the first-and second-forbidden) transitions hlmay also contribute non-negligible e − -capture rates [8,11,20,22,26].…”

“…We intend to use the convolution procedure [2,10,11,21,22] to translate the original electroncapture cross-sections of Ref. [7] to those in the stellar environment by assuming that the parent nuclei and the projectile electrons interact deep in the massive stars' interior. The exotic conditions of such an environment favor the consideration of as many low-lying states as possible during the initial state of the parent nucleus.…”

“…We would like to mention that for the calculation of the absolute (original) e − -capture cross-sections in a laboratory environment (conditions) [5,7], our nuclear method (pn-QRPA) provides state-by-state contributions of exclusive, partial, and total e − -capture rates. The agreement with experimental data [32][33][34][35][36][37][38][39] encouraged us to proceed with the calculations of electron-capture cross-sections in supernova conditions (high densities and high temperatures).…”