Ab initio many-body calculation of the 7Be(p,gamma)8B radiative capture

TL;DR

This paper uses an ab initio no-core shell model combined with the resonating group method to accurately calculate the cross section of the 7Be(p,gamma)8B reaction, which is crucial for solar neutrino studies.

Contribution

It presents a parameter-free, many-body calculation of the 7Be(p,gamma)8B reaction using a chiral nucleon-nucleon interaction within the NCSM/RGM framework, predicting the S-factor shape and normalization.

Findings

Calculated S-factor at zero energy aligns with recent evaluations.

Study of model dependencies on basis size and included states.

Results are consistent with experimental data within uncertainties.

Abstract

We apply the ab initio no-core shell model/resonating group method (NCSM/RGM) approach to calculate the cross section of the 7Be(p,gamma)8B radiative capture. This reaction is important for understanding the solar neutrino flux. Starting from a selected similarity-transformed chiral nucleon-nucleon interaction that accurately describes two-nucleon data, we performed parameter-free many-body calculations that simultaneously predict both the normalization and the shape of the S-factor. We study the dependence on the number of 7Be eigenstates included in the coupled-channel equations and on the size of the harmonic oscillator basis used for the expansion of the eigenstates and of the localized parts of the integration kernels. Our S-factor result at zero energy is on the lower side of, but consistent with, the latest evaluation.