Heavy flavour hadron spectroscopy: an overview

There is strong motivation to understand the effective interaction among heavy quarks and antiquarks since it is expected to be cleaner than those at the light flavor sector. There exist theoretical and experimental evidences to uphold the various predictions of quantum chromo dynamics such as the hadron spectroscopy, decays and production rates etc. The quarkonium and open flavour spectroscopies challenge our understanding of QCD. The field is evolving in an interesting and exciting way, and many years (perhaps decades) of intense effort both on the experimental as well as on the theoretical side is required to understand many of the recently observed exotic hadrons by identifying their status and assigning their spin parity states. In the heavy flavor sector nonrelativistic treatment with constituent quark model is justified and the perturbative QCD contributions (such as one gluon exchange) are more adequate and chiral fields are less important. Here in this talk, a comprehensive over view of the work done during the past few years in the field of heavy flavor hadron spectroscopy will be presented. Apart from the conventional quark structure (quark-antiquarks structure for the mesons and three quarks structure of baryons) of hadrons, the multi-quark hadrons and the hadron molecular states etc., also will be reviewed