Influence of resonances on the 11B(n,gamma)12B capture reaction rate. Capture to the ground state of 12B

TL;DR

This study models the neutron capture on 11B to form 12B, demonstrating that low-lying resonances significantly influence the reaction rate, especially at higher stellar temperatures.

Contribution

It applies the modified potential cluster model with Young diagram classification to describe experimental cross sections and highlights the impact of resonances on reaction rates.

Findings

Resonances above 5 MeV have a significant effect on reaction rates.

E1 transition from the S state explains experimental cross sections at low energies.

Resonance contributions become notable at temperatures above 0.2-0.3 T9.

Abstract

Within the framework of the modified potential cluster model with a classification of orbital states according to Young diagrams, the possibility of describing experimental data for total cross sections of the neutron radiative capture on 11B to the ground state of 12B at energies of 10 meV (1 meV = 10-3 eV) to 7 MeV was considered. It was shown that, taking into account only the E1 transition from the S state of the n11B scattering to the ground state of 12B, it is quite possible to explain the magnitude of the known experimental cross sections at energies of 25.3 meV to 70 keV. Furthermore, on the basis of the total cross sections of 10 meV to 7 MeV, but excluding resonances above 5 MeV, the reaction rate is calculated in the temperature range of 0.01 to 10.0 T9. It is shown that the inclusion of low-lying resonance states makes a significant contribution to the reaction rate, starting already with temperatures of 0.2-0.3 T9.