Thermal dilepton rate and electrical conductivity from quenched lattice QCD
Anthony Francis (Universitaet Bielefeld)

The creation rate of dilepton pairs plays an important role in the research of heavy-ion collisions. At the field theoretical level it is connected to the vector current spectral function.
In lattice QCD the spectral function is related to the Euclidean correlation function via an ill-posed inverse integral transform and solving it usually requires some Bayesian tool like the maximum entropy method (MEM).
I will present a determination of the spectral function for light quarks in the deconfined phase of quenched QCD that does not rely solely on Bayesian methods.
To this extent I show calculations performed in quenched lattice QCD at T=1.45Tc for four values of the lattice cut-off on lattices up to size Ns=128 x Nt=48.
This enables a continuum extrapolation of the correlation function in a large Euclidean time interval to better than 1% accuracy. In addition the first two non-vanishing thermal moments are determined.
I discuss consequences of our findings for the electrical conductivity and dilepton rate in a quark gluon plasma.