Scattering of the Halo Nucleus <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Be</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>11</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math> on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Au</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>197</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math> at Energies around the Coulomb Barrier

Angular distributions of the elastic, inelastic, and breakup cross sections of the halo nucleus $^{11}\mathrm{Be}$ on $^{197}\mathrm{Au}$ were measured at energies below (${E}_{\text{lab}}=31.9\text{ }\text{ }\mathrm{MeV}$) and around (39.6 MeV) the Coulomb barrier. These three channels were unambiguously separated for the first time for reactions of $^{11}\mathrm{Be}$ on a high-$Z$ target at low energies. The experiment was performed at TRIUMF (Vancouver, Canada). The differential cross sections were compared with three different calculations: semiclassical, inert-core continuum-coupled-channels and continuum-coupled-channels ones with including core deformation. These results show conclusively that the elastic and inelastic differential cross sections can only be accounted for if core-excited admixtures are taken into account. The cross sections for these channels strongly depend on the $\mathcal{B}(E1)$ distribution in $^{11}\mathrm{Be}$, and the reaction mechanism is sensitive to the entanglement of core and halo degrees of freedom in $^{11}\mathrm{Be}$.