A non-perturbative contribution to jet quenching

Understand

It has been argued by Caron-Huot that infrared contributions to the jet quenching parameter in hot QCD, denoted by qhat, can be extracted from an analysis of a certain static-potential related observable within the dimensionally reduced effective field theory.

• Following this philosophy, the order of magnitude of a non-perturbative contribution to qhat from the colour-magnetic scale, g^2T/pi, is estimated.
• The result is small; it is probably below the parametrically perturbative but in practice slowly convergent contributions from the colour-electric scale, whose all-orders resummation therefore remains an important challenge.