Spectroscopy of the halo nucleus 11Li by an experimental study of 11Li+p collisions.

An experimental study of $^{11}\mathrm{Li}$+$p$ collisions at $75A$ MeV was performed. The excited state of $^{11}\mathrm{Li}$ at ${E}^{*}=1.25\ifmmode\pm\else\textpm\fi{}0.15$ MeV was observed, which is a candidate for a neutron halo excitation. Four other $^{11}\mathrm{Li}$ states were manifested (at \ensuremath{\sim} 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.