Scattering Of The Halo Nucleus 11Be On A 197Au Target At Energies Around The Coulomb Barrier

Abstract

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 ∼ 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 γ-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.