Quarkonium at Finite Temperature

There was considerable interest in the properties and the fate of heavy quarkonium states at finite temperature since the famous conjecture by Matsui and Satz [1]. It has been argued that color screening in medium will lead to quarkonium dissociation above deconfinement, which in turn can signal quark gluon plasma formation in heavy ion collisions. The basic assumption behind the conjecture by Matsui and Satz was the fact that medium effects can be understood in terms of a temperature dependent heavy quark potential. Color screening makes the potential exponentially suppressed at distances larger than the Debye radius and it therefore cannot bind the heavy quark and anti-quark once the temperature is sufficiently high. Based on this idea potential models at finite temperature with different temperature dependent potentials have been used over the last two decades to study quarkonium properties at finite temperature (see Ref. [2] for a recent review). It was not until recently that effective field theory approach, the so-called thermal pNRQCD, has been developed to justify the use of potential models at finite temperature [3]. This