Quarkonia correlators and spectral functions from lattice QCD

Abstract

Abstract. I discuss recent progress in calculating quarkonia correlators and spectral functions on the lattice in relation with the problem of quarkonia dissolution at high temperatures and heavy quark transport in Quark Gluon Plasma.

SQM 2006: theory summary and perspectives

“…However, QCD lattice gauge-theory calculations of charmonium correlators in recent years have necessitated a revision in our understanding of the dissociation of charmonium states and what it implies for the properties of the surrounding medium: as discussed by P Petreczky at this meeting, the 1S charmonia states (J /ψ, ψ and η C ) survive to unexpectedly high temperatures above 1.5T c and only the 1P states (i.e. the χ C ) dissolves around 1.2T c [120,121]. It is therefore questionable whether the observed charmonium suppression in Pb+Pb collisions at the SPS [122] is truly a smoking gun signature for deconfinement or rather the result hadronic dissociation (see e.g.…”

Charmonia production at SPS energies

“…At present, none of these models seem to accommodate the data. Now, as seen during this conference [18], from recent lattice calculation, the χ c and ψ are predicted to be dissolved at around 1.1 T c , while the J/ψ would still exist at 1.5 T c . At the SPS, the temperature is not expected to rise above 1.5 T c ; this would lead, in a sequential screening scenario, to a suppression of the 40% of J/ψ coming from χ c and ψ decay, while the 60% directly produced J/ψ would remain unaffected at these energy densities.…”

On the temperature dependence of quarkonium correlators

“…In particular, attempts to reconstruct quarkonium spectral functions using the Maximum Entropy Method (MEM) were presented in Refs. [21,22,23,24,25,26,27]. While at zero temperature it is possible to reconstruct the basic features of quarkonium spectral functions the application of MEM above the deconfinement temperature turns out to be problematic [26] The study of the spectral functions using MEM indicated that 1S charmonia may survive in the deconfined phase till temperatures as high as (1.6 − 2.2)T c [22,23].…”