Speaker
Description
The observation of collective-like behaviors in pp and p–Pb collisions at LHC energies has sparked debate about the similarities between the dynamics of small systems and heavy-ion collisions. In this talk, our latest published results are presented, showing baryon-meson $v_{\rm 2}$ grouping (within 1$\sigma$) and significant splitting (approximately 5$\sigma$) at intermediate $p_{\rm T}$ in high-multiplicity p–Pb and pp collisions, similar to those observed in heavy-ion collisions. The Hydro-Coal-Frag model, which incorporates partonic flow and quark coalescence, best describes the data, while alternative models fail to reproduce the pattern, providing strong evidence of a collectively flowing partonic medium in high-multiplicity pp and p–Pb collisions. The key question of how far down in system size the dynamics of small systems and heavy-ion physics remain similar is also investigated. The observed baryon-meson $v_{\rm 2}$ grouping and splitting, down to lower multiplicities $N_{\rm{ch}} > 25 $, suggest that partonic collectivity may persist even in smaller systems. Additionally, our newly published results on ultra-long-range two-particle correlations, $|\Delta \eta| >$ 5.0(6.5), extending down to or below minimum bias multiplicity in pp and p–Pb collisions, explore the limits of collective medium formation in small systems.
The unique sensitivities of flow vector fluctuations to initial geometry and event-by-event fluctuations offer new insights into the initial conditions of both heavy-ion and small collision systems. Newly published results on two-particle correlation observables are presented, revealing $p_{\rm T}$- and $ \eta$-dependent flow vector fluctuations in p–Pb collisions at the LHC, similar to those observed in heavy-ion collisions. These measurements, together with comparisons to state-of-the-art theoretical model calculations, allow us to constrain the initial conditions with unprecedented detail in both transverse and longitudinal directions, advancing our understanding of the origin of anisotropic flow phenomena observed in small collision systems at the LHC.
| Category | Experiment |
|---|---|
| Collaboration (if applicable) | ALICE |
