On the Light Cone Singularity of the Thermal Effective Expansion
  We consider a scalar massless quantum field model, at finite temperature $T$, both renormalizable and asymptotically free. Focussing on the singular structure of the effective perturbation theory about the light cone, several new insights are put forth, regarding the interplay between hard thermal loop resummation and the overall compensation of collinear singularities. 
Thierry Grandou