Barrier distribution from<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">Be</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>9</mml:mn></mml:mrow></mml:mmultiscripts><mml:mrow><mml:mo>+</mml:mo></mml:mrow><mml:mmultiscripts><mml:mi mathvariant="normal">Pb</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>208</mml:mn></mml:mrow></mml:mmultiscripts></mml:math>quasielastic scattering: Breakup effects in the interaction processes

Excitation function of the quasielastic (QEL) scattering at a backward angle was measured for the weakly bound projectile $^{9}\mathrm{Be}$, which bombarded a $^{208}\mathrm{Pb}$ target at near-barrier energies. Barrier distribution was extracted by means of the first derivative of the experimental cross sections with respect to the effective energies. Theoretical fusion barrier distribution has been calculated with the coupled-channels model and compared with the experimental barrier distribution. By this comparison, it is shown that the experimental barrier distribution extracted from QEL scattering is shifted to low energy by 1.5 MeV as compared with the theoretical one. This energy discrepancy between the theoretical prediction and the experimental data indicates the breakup is an important reaction mechanism in the colliding processes of the weakly bound projectile $^{9}\mathrm{Be}$ on a spherical target $^{208}\mathrm{Pb}$.