Fusion of Borromean nucleus ${}^9$Be with ${}^{197}$Au target at near barrier energies

Abstract

To probe the role of the intrinsic structure of the projectile on sub-barrier fusion, measurement of fusion cross sections has been carried out in ${}^9$Be + ${}^{197}$Au system in the energy range E${}_{c.m.}$/V${}_B$ $\approx$ 0.82 to 1.16 using off-beam gamma 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 sub-barrier fusion data. At above barrier energies, the fusion cross section is found to be suppressed by $\approx$ 39(2)\% as compared to the coupled-channel prediction. A comparison of reduced excitation function of ${}^9$Be + ${}^{197}$Au with other $x$ + ${}^{197}$Au shows a larger enhancement for ${}^9$Be in the sub-barrier 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.

Comments: 6 pages, 4 figures, Submitted to Phys. Rev. C