GSI experiments on the synthesis of superheavy elements

Evaporation residue production was investigated at SHIP in cold fusion reactions of Pb- and Bi-target nuclei with projectiles of elements between Ti (Z=22) and Se (Z=34) leading to compound nuclei ZCN=104-116. The isotopes 269110, 271110, 272111, and 277112 of the elements Z=110, Z=111 and Z=112 were unambiguously identified for the first time in bombardments of 208Pb, 209Bi with 62,64Ni and 70Zn. Excitation functions for 50Ti+208Pb and 58Fe+208Pb were measured with high precision, three new spontaneous fission (sf) activities 253104, 254104, 258106 were identified. A small α-decay branch of the even-even nucleus 256104 (bα≅0.003) was confirmed, allowing to estimate mass excesses Δmc2 for N-Z=48 nuclei up to 264Hs (Z=108). An analysis of the α-decay chains observed in a bombardment of 209Bi with 58Fe projectiles showed evidence for an isomeric state in 266Mt (Z=109). We further report on an attempt to produce element 116 and a second isotope of element 112 by the reactions 82Se+208Pb and 68Zn+208Pb, respectively