What perspectives for the synthesis of heavier superheavy nuclei? Results and comparison with models, G. Mandaglio, F.Curciarello, V. De Leo, M. Romaniuk, G. Fazio , G. Giardina, Diраrtimепtо di Fisica dell' Universita’ di Messina, 98166 Messina, Italy and Istitut Nazionale di Fisica Nucleare, Sezione di Catania, 95123, Catania, Italy, А. К. Nasirov, Joint lnstitute fоr Nuclear Research, 141980 Dubna, Russia and Institute of Nuclear Physics, 100214, Tashkent, Uzbekistan − Many Laboratories in the world are strongly engaged to investigate on the massive nucleus reactions with the aim to analyze and understand the characteristics and variety of reaction dynamics, and then to plane new experiments for the synthesis of other heavier superheavy nuclei.  In the last decade many superheavy with Z > 110 were successfully reached by cold and hot fusion reactions (see, for example, Refs. [1]) but in some other cases of symmetric or almost symmetric massive nucleus reactions the investigations led to unsuccessful results [2].  New experiments were performed for searching of superheavy elements with Z=120 [3] and other massive nucleus reactions are thought to be able to reach superheavy elements with Z>120.  The crisis of many recent experimental results does not only base to difficulties in the experiments to reach measurements of evaporation residue cross sections lower than 0.5 pb but also in the inadequateness of models and calculations.  In order to give realistic estimations of cross sections of the reaction products by mass symmetric or almost symmetric entrance channel it is need to develop an adequate model allowing one to describe by a likelihood way the complex dynamics of the mechanisms during all stages of reaction.  The reported difficulties are related not only with reliable theoretical estimations of the fusion cross section — and then of the evaporation residue cross sections — but also in the not univocal experimental identification of quasifission, fast fission and fusion-fission fragments among the large production of fissionlike fragments [4] .  We present and discuss our complete set of results obtained in the framework of the dinuclear system and advanced statistical models [5], also in comparison with the results obtained by other models and in respect of the data where available.  In the context of such reported results [6] and comparison of models, we will discuss about the realistic perspective of the heavier superheavy nucleus formation by complete fusion reaction or eventually by large nucleon number transfer in quasifission process, in very massive nucleus reactions.

 

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