Glimpses of a superheavy element.

Physicists have been synthesizing new elements in the laboratory for nearly 60 years. Most of the artificial nuclei created are highly unstable and last only a fraction of a second. Earlier this year, researchers obtained the first hint that an element with 114 protons in its nucleus would buck the trend of shorter lives for heavier nuclei (SN: 2/6/99, p. 85). Yuri Ts. Oganessian of the Joint Institute for Nuclear Research in Dubna, Russia, and his collaborators now provide details of that discovery in the Oct. 18 PHYSICAL REVIEW LETTERS.

In their initial experiment, the researchers bombarded a plutonium-244 target with calcium-48 projectiles to create a nucleus with 114 protons and 175 neutrons. A follow-up experiment last spring produced evidence that an isotope of element 114 having 173 neutrons had formed. The half-lives of the new isotopes range from seconds to tens of seconds, the researchers estimate. That's almost a million times longer than the life spans of isotopes of elements 110 and 112.