Quasigluon lifetime and confinement from first principles

The mass and the lifetime of a gluon are evaluated from first principles at a finite temperature across the deconfinement transition of pure SU(3) Yang-Mills theory, by a direct calculation of the pole of the propagator in the complex plane, using the finite temperature extension of a massive expansion in the Landau gauge. Even at T=0, the quasigluon lifetime is finite, and the gluon is canceled from the asymptotic states, yielding a microscopic proof of confinement from first principles. Above the transition, the damping rate is a linear increasing function of temperature as predicted by standard perturbation theory.