Fusion-evaporation residues and \alpha-decay chains of the superheavy element Z=115 formed in the 243Am + 48Ca reaction using the dynamical cluster-decay model
Raj Kumar, Kirandeep Sandhu, Manoj K. Sharma, and Raj K. Gupta
Accepted
The decay of Z=115 superheavy nuclear system, formed in $^{243}$Am+$^{48}$Ca reaction, is studied by using the dynamical cluster-decay model (DCM). The calculated excitation functions of 2n, 3n and 4n-evaporation channels, for the excitation energy range $E_{CN}^{*}$=31-47 MeV, are compared with the recent experimental data. The deformation effects are included upto $\beta_2$, with in the hot optimum orientation approach, and a comparative analysis of spherical {\it vs.} static and dynamic deformations is investigated explicitly for the 2n-evaporation residue, as only 2n decay responds to spherical fragments. The 3n and 4n decay cross-sections could be fitted only after the inclusion of deformation effects. The variation of preformation probability, barrier penetrability and barrier modification is investigated in order to extract better picture of the dynamics involved in the reaction under consideration. It is observed that for 3n-evaporation channel, the barrier modification at $E_{CN}^*$=36.15 MeV comes out to be smallest and hence supports the experimental observation of maximum cross-section (8.5 pb) at this energy. The role of isospin (N/Z ratio) is also investigated for the decay of various isotopes of Z=115 formed in $^{48}$Ca+$^{241,243,245}$Am reactions. Furthermore, the evaporation cross-sections of 2n, 3n and 4n-channels are also estimated at Bass barrier by interpolating the neck-length parameters fixed in reference to available data at above barrier energies. Finally, the $\alpha$-decay chains are analyzed by using the preformed cluster model (PCM). It is shown that present data of $\alpha$-decay half-lives prefer the ``hot" optimum orientations of nuclei, rather than the usual ``cold" ones, with in a constant empirical factor in penetrability.