2025/11/10 by João Barata, Kirill Boguslavski, Barata, João +6 · 1 voice · 2 citations
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #High-Energy Particle Collisions Research #Particle Detector Development and Performance #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · doi:10.1103/q8bb-qlm8
openalex publication_date 2026/05/01 · openalex created_date 2026/05/05 · openalex updated_date 2026/06/06
We present the first study of jet substructure modifications during the bottom-up evolution that describes the early stages of heavy-ion collisions. To this end, we study the radiation rate of soft gluons from a hard parton propagating through out-of-equilibrium QCD matter. The gluon spectrum is computed within the improved opacity expansion, which accounts for both multiple soft and single hard momentum exchanges between the hard probe and the medium. The background evolution is obtained from effective kinetic theory simulations that determine the jet quenching parameter, which in turn controls the radiation rate. We compute the radiation rate for initially underoccupied and overoccupied systems, as well as for an expanding system undergoing hydrodynamization, which typically represents the initial stages of heavy-ion collisions. The results for these dynamical backgrounds are compared to static and thermally matched scenarios, allowing to gauge the importance of bulk expansion in the evolution of the jet cascade. Our findings show that the early stages of the bulk matter evolution in heavy-ion collisions leave a sizable imprint on the radiation pattern inside jets. These results establish a basis for incorporating preequilibrium dynamics into realistic descriptions of jet quenching and hard-probe evolution.