Neutron-rich Helium isotopes based on hyperspherical harmonics

We present recent results for neutron-rich Helium isotopes obtained from the hyperspherical harmonics method. Ground-state properties, like the binding energy and the point-proton radius are shown for the two-neutron halo nucleus 6He using two-body low-momentum interactions derived from chiral forces. The applicability of the method to the four-neutron halo nucleus 8He is discussed. As an excited-state observable we present a recent calculation of the nuclear electric polarizability of $^6$He from a semi-realistic potential. A comparison of the calculated quantities to experimental data is performed.