Speaker
Description
The photon emissivity of quark-gluon plasma probes the interactions in
the medium and differs qualitatively between a weakly coupled and a
strongly coupled plasma in the soft-photon regime. The photon
emissivity is given by the product of kinematic factors and a spectral
function associated with the two-point correlator of the
electromagnetic current at lightlike kinematics. A certain Euclidean
correlator at imaginary spatial momentum can be calculated in lattice
QCD and is given by an integral over the relevant spectral function at
lightlike kinematics. I will present a first exploratory lattice
calculation of this correlator. Secondly, I will show how Euclidean
correlators at imaginary spatial momenta can also be used to probe the
regime of deep inelastic scattering off quark-gluon plasma, which
reveals its parton distribution function.
