Our hallmark: MAMI
Originally, the term Mainz Microtron MAMI denotes a high quality particle accelerator for electrons - particles familiar e.g. from the phenomenon of electricity - which has been developed and constructed at the Nuclear Physics Institute of the Johannes Gutenberg University of Mainz, the capital of the state Rhineland-Palatinate of the Federal Republic of Germany. In a broader sense MAMI nowadays stands for our research facility, including not only the MAMI accelerator but also the accompanying experiments.
Our goal: Understanding hadrons
Hadrons are a major class of subatomic particles whose most familiar members are the proton and the neutron, which form the nuclei of atoms and thus account for more than 99.9% of the mass of the visible world around us. Our experimental and theoretical research focuses on hadrons in the low energy domain, i.e. exposed to energies below or around their mass equivalent. Thereby we investigate the details of their substructure, consisting of quarks and gluons, thus filling an important gap within the greater puzzle of the inner workings of our universe.
Our tool: Electron and photon scattering
Our experiments mainly investigate the scattering of electrons or photons - i.e. high-energy gamma-radiation, generated via electrons - off atomic nuclei, which thus experience an energy-momentum- transfer, giving rise to various reactions in response. Since nuclei are composed of protons and neutrons, the most common hadrons, measuring those reactions is our approach to learn about the hadronic substructure. Here the advantage of electrons and photons as a scatter probe is their lack of a substructure and their dominant interaction by quantum electrodynamics, which is well understood. This leads to comparatively simple although rare scattering reactions with the struck nucleus relatively intact, which in turn gives clear and significant experimental results, easier to be interpreted by theory.
Our strength: High precision electrons
The MAMI electron beam excels with its temporal and spatial characteristics, the ability to manipulate its polarisation and, last but not least, the reliability of operation. These features, more subtle but as important as beam energy, which is moderate at MAMI in comparison with other facilities, make most of our experiments possible, enabling them to detect rare scattering reactions with highest precision.
Our other activities: Beyond MAMI
Particle accelerators and scattering experiments cover a great range of energies and particle types, with especially the latter usually requiring an individual large scale accelerator facility for each individual particle combination. Only the combined results from a broad variety of experiments will show if our understanding of nature is correct. Thus we are working with some of the major hadron physics experiments around the world as well as within international collaborations like HadronPhysics2 which coordinate those efforts. There is also an applied science experiment X1 at MAMI, investigating novel X-ray radiation sources, e.g. for medical imaging.