An EFT approach to Color decoherence in jet quenching

Abstract

We use the EFT developed in \cite{Mehtar-Tani:2025xxd}, to understand the interference driven phenomenon of color decoherence in inclusive jet production in a dense nuclear medium such as Nuclei or Quark Gluon Plasma. Using the factorization formula in \cite{Mehtar-Tani:2024smp,Mehtar-Tani:2025xxd}, expressed as a series of multi-sub-jet operators, we define and calculate the contribution of the two sub-jet effective operator. This explicitly reveals the emergent angular scale $θ_c$ that controls color decoherence as well an intricate renormalization group structure for the factorized functions. We show that for a jet of radius R in a medium of size L characterized by a jet quenching parameter $\hat q$, both the LPM effect and color decoherence are controlled by a single dimensionless parameter $\sqrt{\hat q L}LR$ and therefore are equally important for phenomenology. This paper shows how interference driven emergent effects can be included in a factorized framework for computing jet observables in heavy ion collisions.

Figures (7)

• Figure 1: Phase space structure for jet evolution in the medium. The medium resolves multiple hard collinear partons(green) inside the jet (blue). Interaction of these subjets with medium partons(orange) leads to collinear soft radiation(red).
• Figure 2: Real and virtual diagrams of the collinear jet function that contribute to the single sub-jet quark matching co-efficient.
• Figure 3: Diagrams that contribute to the two sub-jet matching co-efficient.
• Figure 4: Real gluon emission diagram for vacuum evolution of two sub-jets. Lines along $n_1$ and $n_2$ are denote the cs Wilson lines in the fundamental and adjoint representation respectively. The black vertices denote the possible attachments of the Feynman diagrams.
• Figure 5: The lines along $n_1$($n_2$) denote cs Wilson lines in the fundamental(adjoint) representation. The black and blue vertices denote the possible attachments for contributing Feynman diagrams.