Beyond the neutron dripline: correlations in multi-neutron systems

At the region of the neutron dripline, the weak binding of valence neutrons leads to the occurrence of unusual phenomena such as halo nuclei and clusters of few neutrons.

Understanding the interaction of neutrons at such extreme conditions of very large isospin asymmetry and low-density environment is fundamental. Multi-neutron systems, as pure neutron systems, can provide an exclusive way to address neutron correlations at the limit of nuclear stability in the absence of the Coulomb interaction.

The question whether such systems can exist led to extensive studies over the years. Experimentally, with the development of radioactive-ion beam facilities, it became feasible to use exotic neutron-rich beams, enhancing the formation of such systems, if these exist.

In this talk I will give an overview of the research field, including the recent result regarding the four-neutron system from the Radioactive Ion Beam Facility in Japan, along with new experimental programs to further study multi-neutron systems.