PROTON RADIOACTIVITY IN HIGHLY DEFORMED NUCLEI has been measured for the first time by a multinational team working at Argonne National Laboratory (Cary Davids, Argonne, 630-252-4062), offering insights into how the distorted shape of a nucleus can affect its radioactivity rates. A rare decay observed mainly in proton-rich isotopes of elements heavier than tin, proton radioactivity occurs when a nucleus ejects a single proton. Using Argonne's ATLAS accelerator to create holmium-141 and europium-131 nuclei, implanting them in a silicon-based detector, and measuring their rates of radioactivity and the energy of the emitted protons, the researchers noted that their data did not match the predictions of the standard theory of proton radioactivity, which assumes a spherically shaped nucleus. Their results only made sense when they used a newer model that allows them to consider the case in which the nucleus has a highly deformed shape, with a length approximately 1.5 times greater than its width (somewhat less distorted than "superdeformed nuclei" which have a ratio of about 2:1). Their data also allowed them to obtain experimental information on the lowest-energy state of a highly deformed nucleus. (Davids et al., Physical Review Letters, 2 March 1998; also see Physics News Preview)