Kaos spectrometer

Since December 2006, the new stage MAMI-C of the Mainz microtron has been accelerating electrons to 1500 MeV energy. Crossing the threshold for kaon generation has opened up new possibilities to study strange hadrons and their interactions in nuclear systems at this precision machine. The study of systems with strangeness provides an additional degree of freedom for the experiments at MAMI to gain deeper insight into the low energy structure of the theory of strong interaction (QCD). While the internal structure of hadrons and their excitation spectra are important aspects of QCD in the low energy limit, it is also important to study how nuclear physics ties in with this theory and how the strongly bound systems emerge from this theory.
The Kaos spectrometer with its short design is used to study the structure of hadrons in (e,e'K) reactions. An important measurement program on the Kaos spectrometer includes the generation of kaons at forward angles. In another program, φ mesons are to be generated inside atomic nuclei and detected by their decay into two kaons. This study allows conclusions to be drawn about quasi-stationary states in cold nuclei at normal nuclear density. The theoretical description of such a system of strongly interacting particles takes up models of the internal structure of hadrons, as well as far-reaching questions about the formation of nuclear structures. For the medium-term future, the scientific program of the project also includes the kaon-associated production of atomic nuclei in which a nucleon has been replaced by a hyperon. The study of these so-called hyperons can shed light on structures that remain hidden in conventional nuclear matter; the hyperon opens up the possibility of selectively studying the hadronic many-body problem, since it is not subject to the Pauli principle and can also populate low-lying nuclear levels.