Heavy quarkonia in quark-gluon plasma

By Cheuk-Yin Wong. 2004

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Q in quenched QCD, we study the binding energies and wave functions of heavy quarkonia in a quark-gluon plasma. By minimizing the grand potential in a simplified schematic model, we find that the proper color-singlet Q- ¯ Q potential can be obtained from the total internal energy U1 by subtracting the gluon internal energy contributions. We carry out this subtraction in the local energy-density approximation in which the gluon energy density can be related to the local gluon pressure by the quark-gluon plasma equation of state. We find in this approximation that the proper color-singlet Q- ¯ Q potential is approximately F1 for T ∼ Tc and it changes to 3 F1 + 1 U1 at high temperatures. In this potential model, the J/ ψ is weakly bound above the phase-transition temperature Tc, and it dissociates spontaneously above 1.62Tc, whereas χc and ψ � are unbound in the quark-gluon plasma. The bottomium states ϒ, χb ,a ndϒ � are bound in the quark-gluon plasma and they dissociate at 4.1Tc, 1.18Tc, and 1.38Tc respectively. For comparison, we evaluate the heavy quarkonium binding energies also in other models using the free energy F1 or the total internal energy U1 as the Q- ¯ Q potential. The comparison shows that the model with the new Q- ¯ Q potential proposed here gives dissociation temperatures that agree best with those from spectral function analyses. We evaluate the cross section for σ (g + J/ ψ → c + ¯ c) and its inverse process to determine the J/ ψdissociation width and the rate of J/ ψ production by recombining c and ¯ c in the quark-gluon plasma.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/a8ae27668bcd2a6891636bfb9823516f8e4efbec

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