New features of the gluon and ghost propagator in the infrared region from the Gribov-Zwanziger approach

Understand

So far, the infrared behavior of the gluon and ghost propagator based on the Gribov-Zwanziger approach predicted a positivity violating gluon propagator vanishing at zero momentum, and an infrared enhanced ghost propagator.

• However, recent data based on huge lattices have revealed a positivity violating gluon propagator which turns out to attain a finite nonvanishing value very close to zero momentum.
• At the same time the ghost propagator does not seem to be infrared enhanced anymore.
• We point out that these new features can be accounted for by yet unexploited dynamical effects within the Gribov-Zwanziger approach, leading to an infrared behavior in qualitatively good agreement with the new data.