Study of strong and weak decay processes of mesons involving heavy avour quarks

The investigation of the properties of mesons composed of a heavy quark and antiquark (cc, bb) gives very important insight into heavy quark dynamics and to the understanding of the constituent quark masses. The theoretical predictions of the heavy quarkonia cc and bb mesons have rich spectroscopy with many narrow states of charmonium lying under the threshold of open charm production and of bottomonium lying under the threshold of open beauty production. Many of these states have not confirmed or understood by experiments. However, there have been renewed interest in the spectroscopy of the heavy flavoured hadrons due to number of experimental facilities (CLEO, DELPHI, Belle, BaBar, LHCb etc) which have been continuously providing and expected to provide more accurate and new information about these states at the heavy flavour sector. According to the notion of asymptotic freedom, the strong interactions become feeble at short distances, so that theoretical analysis can be based on the perturbative application of QCD. The nature of the strong interaction manifests the properties of hadrons and their mutual interactions. The study of heavy flavour and open flavour mesons enable tests of fundamental symmetries, and thereby advances our basic understanding of particle physics. The two-photon and two-gluon annihilation rates of S-wave and P-wave heavy quarkonium are helpful for better understanding the details of quark-antiquark interaction and can function as stringent tests for poten-