Ca + Bk fusion reaction leading to element Z = 117; Long-lived -decaying Db and discovery of Lr
Khuyagbaatar, J.*; Yakushev, A.*; Dllmann, Ch. E.*; Ackermann, D.*; Andersson, L.-L.*; Asai, Masato ; Block, M.*; Boll, R. A.*; Brand, H.*; Cox, D. M.*; Dasgupta, M.*; Derkx, X.*; Di Nitto, A.*; Eberhardt, K.*; Even, J.*; Evers, M.*; Fahlander, C.*; Forsberg, U.*; Gates, J. M.*; Gharibyan, N.*; Golubev, P.*; Gregorich, K. E.*; Hamilton, J. H.*; Hartmann, W.*; Herzberg, R.-D.*; Heberger, F. P.*; Hinde, D. J.*; Hoffmann, J.*; Hollinger, R.*; Hbner, A.*; Jger, E.*; Kindler, B.*; Kratz, J. V.*; Krier, J.*; Kurz, N.*; Laatiaoui, M.*; Lahiri, S.*; Lang, R.*; Lommel, B.*; Maiti, M.*; Miernik, K.*; Minami, Shizu*; Mistry, A.*; Mokry, C.*; Nitsche, H.*; Omtvedt, J. P.*; Pang, G. K.*; Papadakis, P.*; Renisch, D.*; Roberto, J.*; Rudolph, D.*; Runke, J.*; Rykaczewski, K. P.*; Sarmiento, L. G.*; Schdel, M.; Schausten, B.*; Semchenkov, A.*; Schaughnessy, D. A.*; Steinegger, P.*; Steiner, J.*; Tereshatov, E. E.*; Thrle-Pospiech, P.*; Tinschert, K.*; Torres De Heidenreich, T.*; Trautmann, N.*; Trler, A.*; Uusitalo, J.*; Ward, D. E.*; Wegrzecki, M.*; Wiehl, N.*; Van Cleve, S. M.*; Yakusheva, V.*
The superheavy element with atomic number 117 was produced in the Ca + Bk fusion reaction using the gas-filled recoil separator TASCA at GSI in Germany. This result verified the previous result of the discovery of new element 117 reported by Flerov Laboratory of Nuclear Reactions in Russia, which makes certain the synthesis and discovery of element 117 in human history. On the other hand, the last nucleus in the decay chain from the element 117 was assigned to be the unknown nucleus Lr instead of the previously reported Db, and Db was found to be the -decaying nucleus with very long half-life.