## Nuclear Structure

Argonne physicists work to understand the structure of nuclei, both stable and radioactive, found here on Earth and produced in the cosmos. Nuclear structure work at Argonne spans a wide range of phenomena, including:

### Structure of light exotic nuclei

In studying light radioactive, or exotic nuclei, extreme ratios of proton-to-neutron number can be probed, revealing a remarkable range of behavior and allowing us to understand how nuclear forces behave under such extremes.

### Nuclear structure at the limits of stability

The limits of stability can be in terms of the binding energy of nucleons in a nucleus or in terms of other nuclear structure phenomena such as spin. Tracking nuclear structure properties from stability to the extremes can yield essential insights and provide the most stringent challenges of theroretical descriptions.

### Single-particle foundations of nuclear structure

The single-particle framework of nuclei is encapsulated in the hugely successful shell model of nuclei. By using reactions that selectively add and remove individual protons or neutrons, we can reveal underlying single-particle properties. This technique is now being applied to short-lived nuclei.

### Fission and heavy-ion fusion

The break-up of heavy nuclei or the fusing together of lighter ones continues to yield surprising results. For example, the process of fusion between nuclei has been found to be strongly suppressed at energies below the Coulomb barrier, in violation of conventional theories. High-precision, low-background measurements are essential to measure these very low probability reactions.