Effects ofLi10virtual states on the structure ofLi11

The presence of low-lying 1${\mathit{s}}_{1/2}$ virtual state in the n${+}^9$Li system, when included in Faddeev three-body calculations, has a pronounced effect on the structure of the ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ halo. The resulting ${}_{}{}^9{}_{}{}^{}\mathrm{Li}$ momentum distributions, calculated in the Serber model, have a narrow width comparable with the experimental data. The structure of ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ would then have nearly 50% of s-wave motion between the neutrons and the core. The three-body system may also approximately fulfill the conditions for the appearance of Efimov states, and there may exist low-lying excited states near the breakup threshold.