Study Of, Heavy Quarkonium Nature, Heat Medium

QGP is an important state of matter, it is relevant to the early evolution of our universe. At the same time, QCD in high temperature manifests some characteristics, such as the suppressionЛψ, the deconfinement of quarks and the restoration of chiral symmetry spontaneous breaking. Research on QGP is an important topic of particle physics, it is crucial for one to have a deep insight into QCD and to reveal the evolution of the universe. The phase transition phenomenon in QGP has been investigated extensively and deeply, i.e., if a true phase transition happens when a hadron system evolves from hadron phase whose fundamental degrees of freedom are hadrons to QGP, if it happens, what is the nature of this phase transition. The basic theory of QGP is Quantum field theory at finite temperature. At low temperature QGP becomes weakly interacting pion gas while at high temperature, the interaction between quarks and/or gluons is very weak, both cases can be handled effectively by perturbation theory. However, at the vicinity of critical point of a phase transition, the system is composed of both hadrons and quarks and gluons, perturbation theory cannot be applied here. At present, most theoretic study resorts to lattice simulations or phenomenological models based on lattice calculations.Heavy quarkonium physics is the important frontiers in high-energy physics.Historically it played an impor-tant role in establishing Quantum Chromodynamics as a correct description of the basic theory of strong interact-tion.Investigating the effects at various temperature on the masses and decays of quark bound states is an important access to reveal the nature of QGP, especially its nature at critical temperature. In this paper, we will discuss the mass spectrums of heavy quarkonia in QGP. At zero temperature, the quark pair is bound in a potential well due to confinement. When temperature rises, the interaction at large distance between quarks becomes weaker and weaker due to screening effects and confinement vanishes, i.e. deconfinement happens. Now, the quarkonium becomes dissociative and cannot be bound together. Various phenomenological potentials at finite temperature are used to study the charmonium and bottomonium.In this paper we calculate the masses of charmonium and bottomonium with the finite temperature. Our calculations show that the masses of quarkoniam become smaller when temperature rises and the s-wave state for charmonium dissociates at T-1.22Tc and does not dissociate until T-1.98Tc although exited states dissociate at this temperature for bottomonium. At the same time, we calculate the root mean squre radius of heavy quarkoniam too. We also investigate h3S1â†'e+e- and n3S1â†'3g decay width for s-wave state and n3P2â†'rr and n3P2â†'gg decay width for p-wave state. These Decay widths of heavy quarkoniam are proportional to [Rns(0)2/M2] or[Rn1'(0)2/M4] We find dacay width become smaller as the temperture rises. According to the date, we find bottomonium are more stable than charmonium and heavy quarkonium with higher radial excited states and higher rail excited states melt first. At critical temperature, the root mean squre radius increase and wave-function at origin of heavy quarkoniam reduce remarkably, however masses of heavy quarkoniam do not.