Fusion studies in C12+W182,184,186 reactions at energies below and near the Coulomb barrier

Abstract

Background: The coupled-channels model has been highly successful in interpreting experimental subbarrier fusion. The statistical model framework has traditionally been used to explain the basic features of composite system de-excitation in the above Coulomb barrier region. However, in $^{12}\mathrm{C}$-induced reactions with $^{182,186}\mathrm{W}$, measured fusion cross sections are significantly lower than those predicted by various theoretical models and by fusion systematics.Purpose: To investigate the dynamics of heavy ion fusion at energies below and above the Coulomb barrier in the $^{12}\mathrm{C}$-induced reactions.Method: A mass spectrometer was used to study the evaporation residues for the $^{12}\mathrm{C}+^{182,184,186}\mathrm{W}$ reactions. The measurements ranged from $12%$ below to $45%$ above the Coulomb barrier energies. The measured fusion cross sections are compared with coupled channels and statistical model calculations.Results: The measured fusion cross sections for $^{12}\mathrm{C}+^{182,184,186}\mathrm{W}$ reactions show reasonably good agreement with coupled-channel calculations. Also, evaporation residue cross sections for $^{12}\mathrm{C}+^{182,184,186}\mathrm{W}$ reactions in the present experiment along with the fission cross sections from literature are described by statistical model calculations.Conclusions: We successfully explain the previously reported discrepancy between fusion measurements and calculations based on various theoretical models and by fusion systematics for $^{12}\mathrm{C}+^{182,186}\mathrm{W}$ reactions.