Breakdown of the hard thermal loop expansion for quasi-real photons production

We discuss the bremsstrahlung production of soft real and virtual photons in a quark-gluon plasma at thermal equilibrium beyond the Hard Thermal Loop (HTL) resummation. The physics is controlled by the ratio Q(2)/q(0)(2) of the virtuality to the energy. When Q(2)/q(0)(2) much less than g(2), where g is the strong coupling constant, the emission rate is enhanced by a factor 1/g(2) over the HTL results due to light-cone singularities and the bremsstrahlung is induced by scattering of the quark via both transverse and longitudinal soft gluon exchanges.