Researchers have formulated a new theoretical framework to describe the evolution of Quantum Chromodynamics (QCD) particle jets both in vacuum and in the quark-gluon plasma (QGP). This model is based on the resummation of large energy logarithms, exploiting the strong hierarchy between the hard energy scale of the jet and the energy scale associated with its energy loss. The work shows that jet observables near threshold can be formulated in terms of Wilson-line correlators, which obey Banfi-Marchesini-Smye (BMS) evolution.

In this description, soft radiation resolves the internal color structure of the jet, leading to a hierarchy of non-linear evolution equations. These equations govern the evolution of color coherence and the emergence of decoherent energy loss. For jets propagating through a QCD medium, the study demonstrates that medium-induced interactions modify the boundary conditions of the evolution while leaving its ultraviolet structure unchanged. This separation of scales provides a unified description of vacuum-like radiation, medium-induced energy loss, and color coherence.

In the large-$N_c$ limit, the resulting evolution is closely related to the Balitsky-Kovchegov (BK) equation of high-energy QCD. This allows concepts from saturation physics to be applied to jet quenching. In particular, the medium coherence angle plays a role analogous to the saturation scale and acquires the same asymptotic scaling behavior under evolution. This framework establishes a perturbative foundation for the study of color coherence effects in jet quenching and provides a unified picture of soft jet evolution in vacuum and in dense QCD matter.