Speaker
Description
In this talk I will review recent efforts in constraining the photon and dilepton rates on the theory side. This is achieved by extending perturbative calculations to next-to-leading order in the coupling $g$ both for photons and for dileptons in most kinematical regions. A polynomial interpolation for the corresponding spectral function, which vanishes at zero frequency and matches to these perturbative results at large invariant masses is the employed to analyze continuum-extrapolated lattice results for the vector current correlator at spatial momenta $k \sim (2−6)T$. At vanishing invariant mass we extract the photon rate which for k>~ 3T
is found to be close to the NLO weak-coupling prediction. For k <∼ 2T uncertainties are
large, but the photon rate is likely to fall below the NLO prediction, in accordance with the
onset of a strongly interacting behaviour characteristic of the hydrodynamic regime.
