Thermal dilepton rate and electrical conductivity: An analysis of vector current correlation functions in quenched lattice QCD

Understand

We calculate the vector current correlation function for light valence quarks in the deconfined phase of QCD.

• The calculations have been performed in quenched lattice QCD at T=1.45 Tc for four values of the lattice cut-off on lattices up to size 128^3x48.
• This allows to perform a continuum extrapolation of the correlation function in the Euclidean time interval tau*T -in [0.2, 0.5], which extends to the largest temporal separations possible at finite temperature, to better than 1% accuracy.
• In this interval, at the value of the temperature investigated, we find that the vector correlation function never deviates from the free correlator for massless quarks by more than 9%.