PUB - Publikationen an der Universität Bielefeld

We estimate the photon production rate from an SU(3) plasma at temperatures of about 1.1T(c) and 1.3T(c). Lattice results for the vector current correlator at spatial momenta k similar to(2-6)T are extrapolated to the continuum limit and analyzed with the help of a polynomial interpolation for the corresponding spectral function, which vanishes at zero frequency and matches to high-precision perturbative results at large invariant masses. For small invariant masses the interpolation is compared with the next-to-leading-order ( NLO) weak-coupling result, hydrodynamics, and a holographic model. At vanishing invariant mass we extract the photon rate which for k greater than or similar to 3T is found to be close to the NLO weak-coupling prediction. For k less than or similar to 2T uncertainties remain large but the photon rate is likely to fall below the NLO prediction, in accordance with the onset of a strongly interacting behavior characteristic of the hydrodynamic regime.