Aspects of gluon propagation in Landau gauge: spectral densities, and   mass scales at finite temperature
  We discuss a method to extract the K\"all\'en-Lehmann spectral density of a particle (be it elementary or bound state) propagator and apply it to compute gluon spectral densities from lattice data. Furthermore, we also consider the interpretation of the Landau-gauge gluon propagator at finite temperature as a massive-type bosonic propagator. 
Paulo J. Silva, Orlando Oliveira, David Dudal, Pedro Bicudo, Nuno   Cardoso
hep-lat hep-ph