Antimatter-Matter Atoms: A Powerful Tool for Fundamental Physics and Nuclear Research

• Fredrik Olof Andre Parnefjord Gustafsson (CERN)

Room: V225 At the European Organization for Nuclear Research (CERN), there is a unique laboratory known as the Antimatter Factory. In this facility, antiprotons, the antimatter counterparts of protons, are produced and slowed down using the ELENA and Antiproton Decelerator (AD) facilities. These low-energy antiprotons are trapped in sophisticated experiments tailored to test fundamental symmetries of nature, for example, by creating antihydrogen atoms to examine CPT symmetry and the effects of gravity on antimatter. Due to recent advancements in techniques for manipulating antiprotons, there has been a renewed interest in the study of antimatter-matter bound systems, particularly antiprotonic atoms. In these exotic atoms, the heavy antiproton replaces an electron, forming orbits significantly closer to the nucleus than those of bound electrons. As the antiproton cascades to the lower energy levels the electrons are ejected through the Meitner-Auger effect together with the emission of characteristic X-rays following the transitions to the lower energy levels. The energetic transitions can in some cases result in a nuclear resonance effect that can be used to explore short-lived excited nuclear states. Eventually, the antiproton reaches the nuclear periphery where the orbits are perturbed by the strong interaction, leading to its inevitable annihilation on a proton or neutron on the outer ‘skin’ of the nucleus. In this seminar, I will present the exploration of antiprotonic atoms as a probe for nuclear structure studies, and the prospects of new techniques in this context currently under development at the AEgIS experiment at CERN.