2025/12/16 by Sa Wang, Shuang Li, Wang, Sa +7
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Dust and Plasma Wave Phenomena
paper · pdf · doi:10.48550/arxiv.2512.14053
Jet substructure provides a powerful probe of partonic interactions within the quark-gluon plasma (QGP) in heavy-ion collisions. In this paper, we present a systematic theoretical study of the groomed substructures for both inclusive jets and photon-tagged jets (γ+jets) utilizing the Dynamical and Soft-Drop Grooming algorithms in PbPb collisions by employing the SHELL transport model. Our theoretical calculations exhibit a suppression at high k\rm T,g, the relative transverse momentum between the two subjets in the groomed substructure, consistent with the recent ALICE measurements. We show that the suppression of high k\rm T,g arises from the combined effects of the reduction of the subleading subjet transverse momentum due to partonic energy loss and the narrowing of the groomed jet radius Rg induced by selection bias. Our findings demonstrate that no enhancement is observed at high k\rm T,g, even in the complete absence of selection bias. Furthermore, we propose that the broadening of Rg in photon-tagged jets, which are less susceptible to selection bias compared to inclusive jets, provides relatively direct evidence of the jet substructure broadening. Our analysis reveals that the Rg broadening becomes more pronounced as the jet radius increases, where the medium-induced gluon radiation plays a dominant role in driving such broadening. In particular, we find that as the jet radius increases, the Soft Drop grooming algorithm exhibits a better resolving power for the contribution of the medium response to the jet substructure broadening.