Comparing invariant-mass spectroscopy of 8B with ab initio predictions

TL;DR

This study combines experimental invariant-mass spectroscopy of 8B with ab initio theoretical predictions, extending the level scheme and analyzing decay pathways to improve understanding of this nucleus and its mirror.

Contribution

It provides new experimental levels of 8B and compares them with ab initio calculations, enhancing the nuclear structure knowledge of this isotope.

Findings

New levels observed in 8B for Ex<10 MeV.

Good correspondence between predicted and experimental levels for Ex<8.4 MeV.

Decay pathways and prompt/sequential decays analyzed.

Abstract

Levels in 8B have been investigated experimentally using the invariant-mass technique and compared to ab initio calculations. Data sets obtained using E/A=69-MeV 9C and 13O beams on a Be target have been further analyzed to extend the level scheme of 8B for Ex<10 MeV. New levels were observed in the 2p+6Li, p+3He+alpha, and the p+7Be+gamma exit channels. Momentum correlations between the decay fragments were also investigated in order to deduce the decay pathways and whether the decays are prompt or sequential. This nucleus and its mirror were also investigated in the ab initio symmetry-adapted no-core shell model. Correspondence between the newly observed and predicted levels were made based on the level energy and the decay modes. For positive parity levels with J<=3, all predicted levels can be connected to an experimental counter part (as least tentatively) for Ex<8.4 MeV.