Sam Tabor, a professor of experimental nuclear physics at FSU and director of the university's Superconducting Accelerator Laboratory, recently performed the experiment at the GSI laboratory in Darmstadt, Germany, in collaboration with the international team. In the experiment, a cigar-shaped atom was created using a particle collider. To the scientists' surprise, this atom demonstrated a novel kind of radioactive decay by spitting out two free protons at the same time.
Radioactive decay normally involves the emission of one of three types of particle: a helium nucleus consisting of two protons and two neutrons, an electron or a photon. Exotic atoms engineered to contain fewer neutrons than in the atom's natural state were expected to break down by emitting protons one at a time. But the correlated two-proton decay hadn't been seen before and represents a new form of radioactivity.
The team's findings were published in the Jan. 19 issue of Nature, the world's foremost scientific weekly journal.
"The purpose of this line of research is to expand our knowledge of nuclear physics beyond those nuclei present in nature by exploring nuclei with either fewer or more neutrons," Tabor said. "This will help us to understand even the stable nuclei. Another motivation is the fact that such unstable nuclei play important roles in astrophysics and the production of the elements on Earth. We cannot fully understand the astrophysical processes by which even the atoms in our body were produced until we understand the structure of neutron-rich and neutron-poor nuclei."
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Contact: Sam Tabor
tabor@nucmar.physics.fsu.edu
850-644-5528
Florida State University
27-Jan-2006