SFB 443:  Many Body Structure of Strongly Interacting Systems

• Subject Area: Physics
• Term: from 1999 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5483077

The research is centered around the continuous wave electron accelerator MAMI (Mainz Microtron). MAMI consists of an injection linac and three consecutive race track microtrons (RTMs) accelerating electrons to 855 MeV. Presently the laboratory is building a fourth stage which almost doubles the energy to 1500 MeV. High precision investigations of properties of nucleons, nuclei and mesons as well as of their excited states can be performed with MAMI making use of the electromagnetic probe. Typically the momentum transfer of the processes investigated is less than 1 GeV². This characterizes the realm of non pertubative quantum chromo dynamics (QCD) which exhibits a number of unexplained phenomena like the emergence of massive hadrons from almost massless quarks and gluons, which are considered as the fundamental constituents which in turn appear to be unobservable objects (confinement). On the basis of new theoretical developments like chiral perturbation theory, models of effective field theories and also lattice QCD, the high precision data can be related and interpreted. Emphasis is put on the use of polarized beams and targets allowing us to separate experimentally different contributions to scattering processes and thus increasing sensitivities. The increased energy range will allow us to investigate open strangeness production very close to threshold and also the high resolution study of hypernuclei. The study of open strangeness production will help to disentangle the influence of quark masses on hadronic properties.

• DFG Programme: Collaborative Research Centres

Completed projects

• C - Construction, Commissioning and Consolidation of MAMI C (Project Heads Aulenbacher, Kurt ;  Jankowiak, Andreas )
• G01 - Eigenschaften des Nukleons aus der Gitter-QCD (Project Head Wittig, Hartmut )
• H01 - Struktur des Nukleons (Project Heads Arends, Hans Jürgen ;  Scherer, Stefan )
• H02 - Mesonische Struktur des Nukleons (Project Heads Ostrick, Michael ;  Tiator, Lothar )
• H03 - "Seltsame" Hadronen - "Strangeness" in stark wechselwirkenden Teilchen (Project Head Pochodzalla, Josef )
• H05 - Wenig-Nukleonen-System - Hadronen im Medium (Project Heads Distler, Michael O. ;  Heil, Werner )
• H6 - Hadronen im Medium (Project Heads Friedrich, Jörg ;  Walcher, Thomas )
• H07 - Two-Photon-Exchange and Strangeness in the Nucleon (Project Heads von Harrach, Dietrich ;  Maas, Frank )
• Z01 - Geschäftsstelle des SFB (Project Head von Harrach, Dietrich )
• Z02 - Guest Professors and Seminars (Project Head von Harrach, Dietrich )
• Z03 - Technical Coordination and Personnel (Project Head Arends, Hans Jürgen )

• Applicant Institution: Johannes Gutenberg-Universität Mainz
• Spokespersons: Professor Dr. Dietrich von Harrach, until 12/2009; Professor Dr. Michael Ostrick, since 1/2010