Now a group at US Department of Energy's Lawrence Berkeley National Laboratory has managed to confirm the Russian result. Their study is reported in Physical Review Letters.

"By verifying the production of element 114, we have removed any doubts about the validity of the Dubna group's claims," says Professor Heino Nitsche, who co-led the team. "This proves that the most interesting superheavy elements can in fact be made in the laboratory."

Over an eight-day experiment they’ve registered two individual nuclei of the element 114. One was an isotope with 114 protons and 172 neutrons, which decayed in about a tenth of a second, and the other was an isotope with 114 protons and 173 neutrons, which lasted for about half a second.

"One surprise was that the 114 nuclei had much smaller cross-sections – were much less likely to form – than the Dubna group reported," Nitsche said. "We expected to get about six in our eight-day experiment but only got two. Nevertheless, the decay modes, lifetimes, and energies were all consistent with the Dubna reports and amply confirm their achievement."

Search for Island of Stability

Element 114 is of great interest for nuclear physicists, because it is one of the candidates for the so-called Island of Stability, the “Holy Grail” of superheavy elements research. The hypothetical island is a set of isotopes of artificial elements, which are thought to have much greater life spans than their neighbors in the periodic table of elements, lasting for hours, maybe days, or even up to trillions of years, as some scientists hope.

These isotopes are expected to have such an unusual stability because protons and neutrons in their nuclei form complete shells. The heaviest natural isotope with such a configuration is lead, with 82 protons and 126 neutrons. Element 114 isotope with 184 neutrons is the lightest artificial nucleus thought to have this property.

"Based on the ideas of the 1960s, we thought when we got to element 114 we would have reached the Island of Stability. More recent theories suggest enhanced stability at other proton numbers, perhaps 120, perhaps 126. The work we're doing now will help us decide which theories are correct and how we should modify our models," said Ken Gregorich, one of the team’s co-leaders.

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