Eleven new heaviest isotopes of elements Z=105 to Z=117 identified among the products of Bk249+Ca48 reactions

The heaviest isotopes of elements Z=117 to Z=105, ²⁹⁴117, ²⁹³117, ²⁹⁰115, ²⁸⁹115, ²⁸⁶113, ²⁸⁵113, Rg282, Rg281, Mt278, Bh274, and Db270, were identified by means of the Dubna gas-filled recoil separator among the products of the Bk249 + Ca48 reaction. The details of the observed six decay chains, indicating the production and decay of isotopes ²⁹³117 and ²⁹⁴117, are presented and discussed. The decay energies and resulting half-lives of these new nuclei show a strong rise of stability with increasing neutron number, validating the concept of the island of enhanced stability for superheavy nuclei [Oganessian , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.104.142502 104, 142502 (2010)].