Giant Halo at the Neutron Drip Line

Relativistic Hartree-Bogoliubov theory in coordinate space is used to describe the chain of zirconium isotopes reaching from ${}^{116}\mathrm{Zr}$ to the drip line nucleus ${}^{140}\mathrm{Zr}$. Pairing correlations are taken into account by a density dependent force of zero range. For neutron numbers larger than the magic number $N=82\mathrm{}$ a giant neutron halo outside the core of ${}^{122}\mathrm{Zr}$ is predicted. It is formed by up to six neutrons.