What Does Low Energy Physics Tell Us About The Zero Momentum Gluon Propagator

Understand

The connection between QCD, a nonlocal Nambu--Jona-Lasinio type model and the Landau gauge gluon propagator is explored.

• This two point function is parameterized by a functional form which is compatible with Dyson-Schwinger and lattice QCD results.
• Demanding the nonlocal model to reproduce the experimental values for the pion mass, the pion decay constant, $\Gamma_{\pi \rightarrow \gamma\gamma}$ and the light quark condensate we conclude that low energy physics does not distinguish between the so-called decoupling and scaling solutions of the Dyson-Schwinger equations.
• This result means that, provided that the model parameters are chosen appropriately, one is free to chose any of the above scenarios.