Fission and quasi-fission analysis of \(^{252, 254,256}\)No\(^*\) and \(^{249,253,257,261}\)Lr\(^*\) nuclei formed in different reactions

Abstract

In the present work, the capture and fission dynamics of \(Z=\) 102 and 103 nuclear systems are investigated. The coupled channel model and the extended Wong model are used to address nuclear capture as well as fission cross-sections of \(^{48}\)Ca\(+\) \(^{208}\)Pb (leading to the composite system \(^{256}_{102}\)No\(^*\)) and \(^{50}\)Ti\(+^{208}\)Pb (resulting in \(^{258}_{104}\)Rf\(^*\)) reactions in reference to the available experimental data. Furthermore, the isotopic analysis of the \(Z =\) 102 nucleus is performed by changing the mass of the projectile–target (p–t) nuclei that leads to the synthesis of \(^{252,254,256}\)No\(^*\) composite systems. The study suggests relatively higher cross-sections and compound nucleus formation probability (\(P_{\textrm{CN}}\)) values for the reactions in which \(^{48}\)Ca projectile is involved with \(^{208}\)Pb. Also, with a decrease in neutron number for Ca projectile (i.e., \(^{48,46,44}\)Ca with \(^{208}\)Pb target) the fission cross-sections drop by 40\(\%\) which otherwise for Pb target (\(^{208,206,204}\)Pb with \(^{48}\)Ca projectile) is 10\(\%\). Subsequently, an attempt is made to predict the nuclear capture and fission data of \(Z=\) 103 (Lr\(^*\)) nucleus within the mass domain of 249u to 261u (i.e., \(^{249,253,257,261}\)Lr\(^*\)) using various heavy-ion fusion reactions. Along with this, the decay profiles of \(^{249-261}\)Lr\(^*\) composite systems are examined within the framework of the dynamical cluster decay model (DCM) in reference to the fragmentation potential, preformation probability and average total kinetic energy (\(\langle \mathrm TKE\rangle \)) distribution. Apart from traditional Pb-valley, an additional dip around the entrance channel mass asymmetry of \(\eta \approx 0.4\) and \(\eta \approx \) 0.2 is also noted for the reactions under consideration.