Ab-initio calculation of the photonuclear cross section of $^{10}$B

TL;DR

This paper calculates the photonuclear cross section of boron-10 using an ab-initio approach with realistic nuclear forces, achieving good agreement with experimental data and testing the Brink hypothesis.

Contribution

First ab-initio calculation of $^{10}$B photonuclear cross section using the No Core Shell Model with chiral forces and continuum effects.

Findings

Calculated cross section matches experimental data in structure and peak height.

Peak cross section is 4.85 mb at 23.61 MeV.

Verified the Brink hypothesis for $^{10}$B electric-dipole response.

Abstract

We present for the first-time the photonuclear cross section of $^{10}$B calculated within the ab-initio No Core Shell Model framework. Realistic two-nucleon (NN) chiral forces up to next-to-next-to-next-order (N3LO), which have been softened by the similarity renormalization group method (SRG) to $\lambda=2.02$ fm$^{-1}$, were utilized. The electric-dipole response function is calculated using the Lanczos method. The effects of the continuum were accounted for by including neutron escape widths derived from R-matrix theory. The calculated cross section agrees well with experimental data in terms of structure as well as in absolute peak height, $\sigma_{\rm max}=4.85~{\rm mb}$ at photon energy $\omega=23.61~{\rm MeV}$, and integrated cross section $85.36\, {\rm MeV \cdotp mb}$. We test the Brink hypothesis by calculating the electric-dipole response for the first five positive-parity states in $^{10}$B and verify that dipole excitations built upon the ground- and excited states have similar characteristics.