HALO NUCLEI

While neutron halos were discovered 30 years ago, this is the first book written on the subject of this exotic form of nuclei that typically contain many more neutrons than stable isotopes of those elements. It provides an introductory description of the halo and outlines the discovery and evidence for its existence. It also discusses different theoretical models of the halo s structure as well as models and techniques in reaction theory that have allowed us to study the halo. This is written at a level accessible to graduate students starting a PhD in nuclear physics. Halo nuclei are an exotic form of atomic nuclei that contain typically many more neutrons than stable isotopes of those elements. To give you a famous example, an atom of the element lithium has three electrons orbiting a nucleus with three protons and, usually, either 3 or 4 neutrons. The difference in the number of neutrons gives us two different isotopes of lithium, Li6 and Li7. But if you keep adding neutrons to the nucleus you will eventually reach Li11, with still 3 protons (that means it s lithium) but with 8 neutrons. This nucleus is so neutron-rich that the last two are very weakly bound to the rest of the nucleus (a Li9 core). What happens is a quantum mechanical effect