The Structure of Exotic Nuclei 10N and 9C Using the Active Target Approach
MetadataShow full item record
The large imbalance between protons and neutrons and negative binding energy make these nuclei very challenging for experimental studies. Modern theoretical tools have been developed, such as ab initio Greens Function Monte Carlo or the large basis no-core shell model that start from bare nucleon-nucleon interactions or interactions based on the Eﬀective Field Theory and provide exact or truncated solutions to the quantum many body problem. These theoretical approaches can handle up to A=12 nuclei and the study of ^9C and ^10N would provide stringent tests of the theoretical predictions. ^10Li plays an important role in the Borromean system ^11Li which is a two neutron halo system with two valence neutrons extending far beyond the ^9Li core. To model ^11Li, we most know about the ^9Li+n interaction that can be established from the known states in ^10Li. There are uncertainties in the spin-parity assignments and excitation energies of low-lying states in ^10Li and even less is known about its mirror nucleus, ^10N. We report on the ﬁrst observation of the ground and ﬁrst excited states in ^10N via ^9C+p resonance scattering. Both states were determined to be ℓ = 0. We can now reliably place the location of the 2s1/2 shell in ^10N at 2.3 ± 0.2 MeV above the proton decay threshold. Using mirror symmetry and correcting for Thomas-Ehrman shift we argue that the ground state of ^10Li is an ` = 0 state that should be very close to the neutron threshold. The structure of ^9C was studied using ^8B+p resonance scattering with the newly commissioned Texas Active Target (TexAT) detector system. Recent theoretical developments allow for robust predictions of level structure of light nuclei, including continuum eﬀects, starting from nucleon-nucleon and three-nucleon interactions [1, 2, 3]. High-quality experimental data are necessary to benchmark these predictions. Experimental data on ^9C is limited -only two excited states in ^9C have been observed. The goal of this work was two-fold. First, the ^8B+p resonance scattering was used as the ﬁrst commissioning experiment for the active target detector system TexAT. This reaction was chosen because the experimental data on ^8B+p elastic scattering excitation function at low energy are available. The second goal was to search for positive parity states in ^9C (none are known). For that, we extended the ^8B+p elastic scattering excitation function to higher excitation energy, improved statistics and quality of the existing low energy data, measured angular distributions, and also searched for the ^8B(p,2p) reaction channel.
Hooker, Joshua Lee (2019). The Structure of Exotic Nuclei 10N and 9C Using the Active Target Approach. Doctoral dissertation, Texas A&M University. Available electronically from