Experiment Facility Process Babar SLAC, Stanford, USA Electron-Positron Collider Belle KEK, Tsukuba, Japan Electron-Positron Collider BES-III BES, Beijing, China Electron-Positron Collider CDF Fermilab, Chicago, USA Proton-Antiproton Collider CLEO CESR, Ithaca, USA Electron-Positron Collider D0 Fermilab, Chicago, USA Proton-Antiproton Collider LHCb CERN, Geneva, Switzerland Proton-Proton Collider Table 1.1: Experiments that have detected heavy quarkonium-like states. mesons are composed of a quark and an antiquark. It should be emphasized that the quark model does not describe the dynamics of quarks. Rather, it is a classification scheme that successfully explains the large variety of hadrons as various combinations of a small number of quarks. Quantum Chromodynamics (QCD) successfully describes the interactions of quarks, and as such, it is a fundamental theory of the strong nuclear force. However, it is not clear how the quark model of hadrons emerges from QCD. Interestingly, QCD seems to suggest that a much richer spectrum of hadrons is possible than the simple baryons and mesons of the quark model. These hadrons that exist outside the quark model are called exotic hadrons. To date there is no unambiguous proof for the existence of any exotic hadron, although the Z ± c (3895) is a very strong candidate. There are experimentally established hadrons that are difficult to interpret within the quark model and are often speculated to be exotic hadrons. It has been widely speculated that some of the heavy quarkonium-like states may be exotic hadrons. In order to investigate this possibility, theoretical calculations are needed to firmly establish the expected properties of exotic hadrons. The methods of QCD sum rules (QSR) can be used to predict the physical properties of exotic hadrons that may exist in the same mass region as heavy quarkonia. This is the main motivation for the research presented in 2