Charm and its production in neutrino reactions

The present thesis gives a survey about the status of the studies of charmed particles. First the quark model is explained. Then it is shown how the spectroscopy of hadrons is extended, if one goes on from the three-quark model to the four-quark model. In the third chapter it is explained how from the weak interaction on the existence of the charmed quark can be concluded. Thereafter the evidences of the existence of a fourth quark from the e+e- annihilation are descrbed. Here also the detection of the J/psi is discussed which could be interpreted as bound state of a new quark-antiquark system and therefore proved the existence of a new quark. In the fifth chapter the production of charmed particles in neutrino experiments is described. Lepton pair events are discussed which showed that the fourth quark is identical with the theoretically predicted charmed quark. The sixth chapter deals with the direct observation of charmed particles in neutrino reactions and finishes with a determination of the production rate of charmed particles in the framework of the quark-parton model. In the seventh chapter the production of charmed particles in electromagnetic and hadronic interactions is discussed. Thereafter follows in the eight chapter a discussion of the decays of charmed particles. (orig./HSI)