Fusion barrier distribution described by above-barrier resonances Original Research Article

We have constructed an analytically solvable, smooth, short-ranged, realistic and composite barrier potential with parameters controlling the flatness at the top, the range and the asymmetry of the barrier. When certain condition on flatness is obeyed, the transmission coefficient (T) across this barrier is found to be oscillatory in the above-barrier region of energy representing above-barrier resonances (ABR). Using this T with proper dependence on angular momentum, we estimate the results of fusion cross section View the MathML source and the distribution function View the MathML source in the cases of two best studied examples namely 16O +144Sm and 16O +208Pb systems. On comparison with the corresponding experimental data we find good explanations of these fusion data. The asymmetry in the composite barrier addresses the problem of sub-barrier enhancement of View the MathML source data. On the other hand, for the first time, the oscillatory structure in the results of View the MathML source is proved to be the manifestation of ABR sustained by the composite barrier by virtue of its flatness at the top.