Speaker
Description
Recent CMS data revealed intriguing long-range correlations within high-multiplicity jets produced in proton-proton collisions, suggesting the potential onset of collective behavior, typically associated with heavy-ion collisions, at much smaller scales. Two-particle correlations in the “jet frame” show a surprising rise in elliptic flow harmonics, v2, at large pseudorapidity separations (Δη > 2), in jets with high charged-particle multiplicities, a trend not reproduced by event generators like Pythia and Sherpa. In this talk, we present new measurements on the long-range near-side correlations in the jet frame, along with the transverse momentum and ∆η* dependence of elliptic and triangular flow, across a wide range of jet multiplicity and transverse momentum. We further explore the role of jet substructure in driving the observed long-range azimuthal correlations. By selecting jets exhibiting prominent two-prong structures and comparing the results with models incorporating final-state rescatterings, we investigate the potential connection to the geometry of the initial-state jet system. These results offer fresh insights into collective effects at the smallest scales, potentially reshaping our understanding of QCD dynamics in its nonperturbative regime.
