Speaker
Description
High-multiplicity proton-proton (pp) and proton-lead (p-Pb) collisions at the LHC have revealed that even smaller collision systems show the onset of phenomena typical of heavy-ion collisions. Strangeness enhancement and collective flow, two examples of such phenomena, suggest that light-flavor hadron production arises from complex mechanisms of which relative contributions evolve smoothly from low to high multiplicity collisions across different collision systems. Furthermore, observations suggest that the relative contributions of different processes evolve smoothly from low to high multiplicity collisions. This is puzzling in a theoretical context, since it implies that pp collisions cannot be seen as an incoherent sum of parton-parton scatterings, contrary to the modelization in most Monte Carlo event generators, such as PYTHIA. Moreover, these signatures have historically been attributed to the strongly interacting medium formed in heavy-ion collisions, which challenges current theoretical frameworks in the context of smaller collision systems.
Studies on multi-differential strange particle production in small systems can be utilized to gain insight into the various final state effects at play and represent an essential baseline for heavy-ion studies. This contribution presents new results from ALICE on light-flavor particle production as a function of the transverse spherocity in pp collisions, measured at \sqrt{s} = 13 TV. Events that are either "isotropic" (dominated by multiple soft processes) or "jet-like" (dominated by one or few hard scatterings) can be selected utilizing narrow selections in multiplicity and spherocity. Predictions from state-of-the-art Monte Carlo generators are compared with the obtained experimental results.
