AGATA: Precision Spectroscopy of Exotic Nuclei

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AGATA is a tool specifically designed to enable precision spectroscopy of excited nuclear states. A powerful gamma-ray spectrometer is essential for nuclear structure studies, and AGATA - as Europe's leading gamma-ray device - is in very high demand at all the major European facilities that require in-beam gamma-ray spectroscopy capability for their science programmes. The AGATA science is, therefore, exceptionally broad-ranging and is strongly connected to the long-term plans for nuclear-structure physics at these facilities. The science programme is well aligned with the STFC Science Challenges, from which priorities emerge, highlighted in the STFC Nuclear Physics Roadmap. These include: What determines the limits of nuclear existence and are there new forms of structure and symmetry at the limits of nuclear binding? What mechanism drives the emergence of simple patterns in complex nuclei? The study of structure at the very limits of nuclear stability is crucial, for example, in order to understand the isospin dependence of the effective nuclear interaction, to explain collective phenomena from the properties of the individual nucleons, and to establish the limits of nuclear existence. It has become clear that many of our textbook ideas of nuclear structure need to be revised. For example, the values of the magic numbers in the nuclear shell model are no longer sacrosanct and the strength of the nucleon-nucleon interaction means that the position of the neutron (proton) shell closure varies with the proton (neutron) number. The number of neutron-rich nuclei which can exist is now expected to be far greater than previously thought: improvements nuclear theory, including more realistic estimates of correlations and clustering, predict a neutron drip-line which seems to be constantly receding. The combination of the high resolving power of AGATA with the new high-intensity radioactive ion beam facilities will provide a step-change in our capability to address these emerging challenges.