Fusion of the Borromean nucleus Be 9 with a Au 197 target at near-barrier energies

To probe the role of the intrinsic structure of the projectile on subbarrier fusion, measurement of fusion cross sections has been carried out in a Be9 + Au197 system in the energy range Ec.m./VB≈ 0.82 to 1.16 using off-beam γ-counting method. Measured fusion excitation function has been analyzed in the framework of the coupled-channel approach using CCFULL code. It is observed that the coupled-channel calculations, including couplings to the inelastic state of the target and the first two states of the rotational band built on the ground state of the projectile, provide a very good description of the subbarrier fusion data. At above-barrier energies, the fusion cross section is found to be suppressed by ≈39(2)% as compared to the coupled-channel prediction. A comparison of reduced excitation function of Be9 + Au197 with other x + Au197 shows a larger enhancement for Be9 in the subbarrier region amongst Z=2-5 weakly and tightly bound projectiles, which indicates the prominent role of the projectile deformation in addition to the weak binding.