Spectroscopy of the halo nucleusLi11by an experimental study ofLi11+pcollisions

An experimental study of ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$+$p$ collisions at $75A$ MeV was performed. The excited state of ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ at $E^{*}=1.25\mathrm{}\pm 0.15$ MeV was observed, which is a candidate for a neutron halo excitation. Four other ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ states were manifested (at ∼ 3.0, 4.9, 6.4, and 11.3 MeV). Angular distributions were measured for elastic scattering ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$+$p$ and 8He+$p$. Structure of the ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ halo was investigated using the eikonal approach.