The nature of the neutron - dark, devious, or social?
by
Thomas Nilsson(Chalmers)
→
Europe/Stockholm
Description
The discovery of the neutron by J. Chadwick in 1932 yielded the missing building block of the atom, following the electron and the proton. However, almost a century later, the neutron remains partly mysterious; there is a remaining disagreement in measurements of its lifetime that has been suggested to connect to a “dark decay” process. Neutrons are as well the tool for probing fundamental symmetries, like baryon number violation in possible neutron-antineutron oscillation experiments.
However, also in their role of building blocks, neutrons still raise questions. Being neutral, there is no Coulomb repulsion prohibiting multi-neutron systems, i.e. neutral nuclei to form. This element, with atomic number zero, is in popular science coined neutronium. Bound and resonant multi-neutron systems, especially the tetraneutron, has been searched for in decades, albeit modern few-body theories generally rule out at least the existence of a bound system. However, an experiment using the Radioactive Ion Beam Factory at RIKEN, Japan did recently find tantalizing evidence for a narrow structure that could be the tetraneutron. In my talk, I will focus on the experimental efforts leading up to this discovery, and how to further explore the "social" aspects of the neutron.
