Search

The angular distributions of the elastic, inelastic scattering and break-up cross sections of the one neutron halo $^{11}$Be on a heavy-mass target ($^{197}$Au) have been measured at laboratory energies below (31.9 MeV) and around (39.6 MeV) the Coulomb barrier ($V_b \sim$ 40 MeV). The elastic, inelastic channel and break-up channels of the $^{11}$Be + $^{197}$Au reaction have been experimentally separated for the first time in this energy range. The experiment was performed at TRIUMF, using four Silicon detectors in telescope configuration to separate the $^{11}$Be from the $^{10}$Be fragments and the High-Purity Germanium Detector Array TIGRESS for $\gamma$-ray detection. The break-up and inelastic scattering contributions are observed to be relevant even at energies well below the Coulomb barrier. Data are compared with different models of increasing degree of sophistication: semiclassical, inert-core continuum discretised coupled channel (CDCC) calculations and CDCC including core deformation and excitations (XCDCC). XCDCC calculations are necessary to reproduce simultaneously elastic, inelastic and break-up scattering data. The results show that the reaction mechanism is sensible to the entanglement of core and halo degrees of freedom in $^{197}$Au.