Halo Nuclei: Stepping Stones Across the Dripline

Abstract

The availability of intense secondary beams in conjunction with efficient detection setups allows for a production and study of the most extreme nuclear systems, in terms of asymmetry of proton and neutron number, in the continuum. They can be produced via transfer and knockout reactions, depending on beam energies, with beams of nuclei close to the driplines, exhibiting exotic properties themselves, as seeds. These nuclear open quantum systems far from the valley of beta stability challenge nuclear structure theory being as well as reaction theory that tries to describe their production mechanisms. Due to their strong clustering they exhibit a rather clean few-body character. From experiments momentum distributions, relative energy spectra, and spin alignment during the reaction can be determined, which leads to the observation of energy and angular correlations as well as dependent quantities like e.g. the profile function denoting a momentum width in dependence of relative energy. They are determined from momentum vectors of fragments and gamma radiation leaving the reaction zone. The link to intrinsic properties of these unbound systems has to be explored by gathering precise knowledge of the properties of the seed nuclei and compare them to the structures observed in the continuum. In this paper I will exemplify the above-mentioned methods, and apply them particularly to light systems like 10He, 10−13Li, and neutron-rich Beryllium systems. Furthermore, perspectives for the 7H and heavy Oxygen systems are discussed.