In February 2004 four atoms of Element 115 have been created by firing a beam of calcium-48 ions at a target of americium-243. It seemed to have a fairly long lifetime of about 90 milliseconds suggesting it is near to the predicted 'island of stability'. Two isotopes of element 115 were produced, 115-288 when 3 neutrons were emitted from the interaction of Am-243 with Ca-48, and 115-287 when 4 neutrons were emitted instead.

The four atoms were observed to decay first to element 113 by alpha decay, and thence by further alpha decays to elements 115, 113 and 111 and finally by 3 more alpha decays to element-105, Dubnium. One of the nuclei took over a second to decay to element 111. Three of the decays ended up at Db-268, an isotope with a very long half-life (for that part of the Segre chart) of 16 hours. The fourth chain ended up at Db-267 when the energy of the colliding Ca-48 ions was slightly increased above the 248MeV used for the other three collisions. The whole alpha decay chain from element 115 to Dubnium took less than 30 seconds.

²⁸⁷Uup₁₁₅ → ²⁸³Uut₁₁₃ + ⁴He₂ (46.6 milliseconds) → ²⁷⁹Uuu₁₁₁ + ⁴He₂ (147 milliseconds)

²⁸⁸Uup₁₁₅ → ²⁸⁴Uut₁₁₃ + ⁴He₂ (80.3 milliseconds) → ²⁸⁰uuu₁₁₁ + ⁴He₂ (376 milliseconds)

²⁸⁸Uup₁₁₅ → ²⁸⁴Uut₁₁₃ + ⁴He₂ (18.6 milliseconds) → ²⁷⁹Uuu₁₁₁ + ⁴He₂ (1196 milliseconds)

²⁸⁸UUp₁₁₅ → ²⁸⁴Uut₁₁₃ + ⁴He₂ (280 milliseconds) → ²⁷⁹Uuu₁₁₁ + ⁴He₂ (517 milliseconds)