A lattice QCD calculation of the charmonium spectrum

On November 11, 1974 the $J/\Psi$ charmonium particle was discovered simultaneously on both coasts of the United States. This state is mainly built up from a charm quark and an anti-charm quark. Until then only three so-called flavors of quarks were known experimentally: up, down and strange. Since then several new charmonium resonances have been discovered whose properties could mostly be accounted for by nonrelativistic potential models with a confining force. However, many of the very recent discoveries are at variance with this simplistic picture. One such example is the so-called $X(3872)$ particle. Future dedicated experiments like {\it PANDA} at {\it FAIR} in Darmstadt are expected to produce large charmonium data samples that will help to further explore the properties of old and new such states. Quarks are an elementary building block of visible matter. They interact via the strong interaction, which is described by the theory of {\it Quantum Chromo Dynamics (QCD)}. With the help of numerical simulations in the framework of {\it Lattice QCD}, i.e. QCD on a discretized spacetime, this work tries to shed light on the masses and structure of charmonium states, including the more exotic ones