Difference in evaporation residue yields in the cold and hot fusion reactions

An interest to study the mechanism of the complete fusion with massive nucleus reactions was caused by difficulties of synthesizing superheavy elements due to their small cross sections. Theoretical models used to obtain knowledge about fusion mechanism in heavy ion collisions at low energies are requested. We present the theoretical results of the compound nucleus (CN) formation and evaporation residue (ER) cross sections obtained for the 48Ca+ 248Cm and 58Fe+232Th reactions leading to the formation of CN with A 296 and A 290 of the superheavy element Lv (Z 116), respectively. The ER cross sections, which can be measured directly, are determined by the complete fusion and survival probabilities of the heated and rotating CN. Those probabilities can not be measured unambiguously but the knowledge about them is important to study the formation mechanism of the observed products and to estimate the ER cross sections of the expected isotopes of elements. For this aim, the 48 Ca+249 Cf and 64Ni+232Th reactions are also considered. The survival probability of the heated and rotating CN is sensitive to the used mass and shell correction values of superheavy nuclei. The ER cross sections obtained by using the macroscopic-microscopic model with mass and fission barrier values calculated by Warsaw group lead to smaller ER values for all reactions in comparison with the case when the masses and shell correction calculated by P. Möller et al are used.