Clusters, Halos, And S-Factors In Fermionic Molecular Dynamics

TL;DR

This paper presents a flexible Fermionic Molecular Dynamics approach that accurately describes various nuclear states, including exotic halos and cluster states, and successfully computes astrophysical S-factors for nuclear reactions.

Contribution

It introduces a versatile basis in Fermionic Molecular Dynamics capable of modeling both shell-model and exotic nuclear states, enabling precise microscopic calculations of nuclear reactions.

Findings

Accurately describes halo and cluster states in nuclei.

Successfully computes astrophysical S-factors matching experimental data.

Demonstrates the method's flexibility for diverse nuclear phenomena.

Abstract

In Fermionic Molecular Dynamics antisymmetrized products of Gaussian wave packets are projected on angular momentum, linear momentum, and parity. An appropriately chosen set of these states span the many-body Hilbert space in which the Hamiltonian is diagonalized. The wave packet parameters - position, momentum, width and spin - are obtained by variation under constraints. The great flexibility of this basis allows to describe not only shell-model like states but also exotic states like halos, e.g. the two-proton halo in 17Ne, or cluster states as they appear for example in 12C close to the \alpha-breakup threshold where the Hoyle state is located. Even a fully microscopic calculation of the 3He(\alpha,\gamma)7Be capture reaction is possible and yields an astrophysical S-factor that compares very well with newer data. As representatives of numerous results these cases will be discussed in this contribution, some of them not published so far. The Hamiltonian is based on the realistic Argonne V18 nucleon-nucleon interaction.