Recently, Dr. Xing Wenjing, a specially funded postdoctoral researcher at the Institute of Frontier and Interdisciplinary Science of Shandong University, has made significant progress in the theoretical study of jets in relativistic heavy-ion collisions. For the first time, the energy-energy correlators (EEC) of particles within light and heavy flavor jets through the quark-gluon plasma (QGP) were simultaneously investigated using comprehensive numerical simulations. This work revealed that the unique structure of EEC can shed light on the complex physical mechanisms of jet interactions with an extremely hot nuclear matter. The findings were published in Physical Review Letters titled "Flavor Hierarchy of Jet Energy Correlators inside the Quark-Gluon Plasma." Xing Wenjing is the first author of the paper, with her advisor Prof. Cao Shanshan, as well as collaborators from Central China Normal University Prof. Qin Guangyou and Prof. Wang Xinnian, serving as co-corresponding authors.

High-energy collisions of nucleons or nuclei can produce energetic quarks and gluons, which subsequently undergo parton shower and fragmentation processes to form collimated beams of hadrons, known as jets. Quantum Chromodynamics (QCD) theory predicts that the parton shower process of massive particles can be significantly suppressed within a forward cone, a phenomenon known as the "Dead-cone Effect." Studying the dead-cone effect is one of the important ways to test and develop the QCD theory. In 2022, the LHC-ALICE Collaboration successfully extracted the splitting vertices and angles of D-meson and inclusive jets via iterative declustering techniques in proton-proton collisions. By comparing the splitting angles between these two types of jets, they provided the first experimental confirmation of the dead-cone effect for heavy quarks, with the results published in Nature. However, the dead-cone effect in heavy-ion collisions and its modification by nuclear matter at extremely high temperatures have yet to be experimentally verified.

The EEC of particles within jets has recently emerged as a novel observable in jet physics, gaining significant attention due to its sensitivity to various physical quantities across different scales. This study, for the first time, simulated the realistic interactions of both light and heavy flavor jets with a QGP medium. From these simulations, the EECs of heavy and light flavor jets were calculated. The results demonstrate that the dead-cone effect of heavy quarks leads to a significant dependence of the jet EEC on the jet flavor: compared to that of inclusive jets, the EEC of heavy flavor jets has a weaker magnitude and peaks at larger angles. Furthermore, compared to proton-proton collisions, the jet EEC in heavy-ion collisions exhibits rich nuclear modification structures: they are suppressed at intermediate angles but enhanced at small and large angles. This reflects an interplay between a variety of physical effects, including mass effect, parton energy loss, gluon bremsstrahlung, and medium response inside a hot nuclear matter. This work provides a new perspective for exploring the properties of strongly interacting matter using jets and offers important theoretical insights for future high-energy nuclear physics experiments.

This research was supported by the National Natural Science Foundation of China and the China Postdoctoral Science Foundation.