Study of constant mode in charmonium correlators at finite temperature

Recent studies on the spectral function of charmonium in lattice QCD suggest survival of J/ψ state in the deconfinement phase till relatively high temperature. Based on the studies, different scenarios of J/ψ suppression are discussed to understand experimental results in the Heavy Ion Collision experiments. The scenarios require the information on the dissociation temperatures of χc and ψ ′ as well as that of J/ψ . In order to investigate these states in finite temperature lattice QCD, we have to consider an effect of a characteristic constant mode in the correlators. As a result of the study on the constant mode, we find that most drastic change in charmonium correlators for χc states just above the deconfinement transition are caused by the constant mode. It may indicate the survival of χc states after the deconfinement transition until, at least, 1.4Tc.