Description
Abstract: The electromagnetic moments and charge radii of nuclear ground- and excited states provide nuclear-model independent insight into the structure of atomic nuclei, and serve as critical benchmarks for the testing and development of theoretical models. Measurement of these observables in exotic isotopes, here defined as being far from the valley of stability or at high nuclear excitation energy, is crucial as it allows a probe of the nuclear force under extreme conditions. As a highly interdisciplinary science, bridging nuclear, atomic, solid-state and recently also molecular physics, promising and ambitious research directions lie ahead. This interdisciplinarity is also reflected through an active dialogue between experimentalists and state-of-the-art nuclear, atomic, molecular and solid-state theorists; this dialogue is essential in building an improved understanding of the nuclear forces inside the nuclear medium. This document outlines the ongoing and extensive technical development work which is being undertaken in order to study increasingly exotic systems. These developments take place at several frontiers: the precision frontier, which seeks to provide access to new observables hitherto unexplored in radioactive systems; the sensitivity frontier, which seeks to enable the study of increasingly rare and exotic isotopes; and a ‘complexity’ frontier which seeks to enable the study of systems with complex atomic structure and/or chemical properties, so far largely unexplored. This activity takes place at all major radioactive ion beam laboratories in Europe, complementing one another on all these frontiers, and is furthermore strongly supported by developments in several European university laboratories.