Entrance channel-dependent compound nucleus formation probability of heavy nuclei

Abstract

Compound nucleus (CN) formation probability (\(P_{\textrm{CN}}\)) is essential for synthesising superheavy elements (SHEs), understanding nuclear reactions, predicting reaction outcomes and designing efficient experiments. High \(P_{\textrm{CN}}\) indicates a greater likelihood of successful fusion, aiding in the study of nuclear stability and structure. An empirical formula for \(P_{\textrm{CN}}\) has been proposed, incorporating new parameters such as effective fissility (\(\chi _{\textrm{eff}}\)) and zeta parameter (\(\zeta \)), along with excitation energy and fusion barrier height. The fitted function shows greater systematic behaviour for \((E^*-V_B)\chi _{\textrm{eff}}\) and \(\zeta ^{0.02}\). \(P_{\textrm{CN}}\) values obtained align well with the experimental data, predicting outcomes for both successful and unsuccessful fusion reactions. Notably, larger \(P_{\textrm{CN}}\) values are seen for \(\phantom {a}^{45}\hbox {Sc}{+}^{249}\hbox {Cf}\) and \(\phantom {a}^{50}\hbox {Ti}{+}^{249}\hbox {Bk}\) for \(Z=119\) and 120, respectively. Analysis identifies \(\phantom {a}^{80}\hbox {Se}{+}^{210}\hbox {At}\) and \(\phantom {a}^{55}\hbox {Mn}{+}^{241}\hbox {Pu}\) as potential reactions for synthesising the SHE (\(Z=119\)), with Mn projectiles showing higher \(P_{\textrm{CN}}\) than Se projectiles due to lower \(\zeta \) and deformation effects. Hence, \(\phantom {a}^{55}\hbox {Mn}{+}^{241}\hbox {Pu}\) is more promising than \(\phantom {a}^{80}\hbox {Se}{+}^{210}\hbox {At}\) for this purpose. The present work is useful for focussing experimental efforts and increasing the efficiency of SHE research by focussing on reactions with higher CN formation probability.