Proton Emitters: A Laboratory for Detailed Nuclear Structure Studies Beyond the Drip Line

The structure of nuclei situated far from the line of β stability is presently one of the major thrusts in nuclear physics. The phenomenon of proton emission offers a unique opportunity to study nuclei beyond the proton dripline. Within the last decade proton-decay studies have been transformed from a curiosity in to a powerful spectroscopic tool. Experimental effort has resulted in the observation of deformed proton emitters, the discovery of proton-decay fine structure and the observation of excited states in several proton emitters. Thank to continuous progress in experimental techniques the body of data on proton emission is steadily increasing. Several theoretical models have been developed to quantitatively reproduce proton-decay widths. The role of Coriolis mixing, non-axial degrees of freedom, proton-neutron interaction, coupling to core vibrations are some of the aspects currently under investigation. This paper discusses recent progress on the understanding of proton decay. It will be illustrated by experimental results obtained at the Argonne National Laboratory within the last 2 years. (author)