Abstract
Studies of jet production can provide information about the properties of the hot and dense strongly interacting matter created in ultra-relativistic heavy-ion collisions. Specifically, measurement of strange particles in jets may clarify the role of fragmentation processes in the anomalous baryon to meson ratio at intermediate particle pT that was observed in lead-lead (Pb–Pb) and, to a lesser extent, in proton-lead (p–Pb) collisions.In this contribution, measurements are presented of the pT spectra of baryons and mesons produced in association with charged jets in Pb–Pb collisions at and p–Pb collisions at . The analysis is based on data recorded by ALICE at the LHC, exploiting its excellent particle identification capabilities. The baryon/meson ratios of strange particles associated with jets are studied for different event activities in p–Pb collisions and are restricted to central events in Pb-Pb collisions. A comparison is shown to the ratios obtained for inclusive particle production and for particles stemming from the underlying event as well as to PYTHIA proton-proton (pp) simulations.
Highlights
The first measurements of the baryon-meson ratio in heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) showed an enhanced baryon/meson production at intermediate transverse momentum [1, 2] relative to pp collisions
For the analyses presented in this contribution, the pT spectra of strange particles associated with jets are studied for events with different event multiplicities in p–Pb collisions and for the 10% most central events in Pb–Pb collisions
The V0 candidate is associated to the jet cone if the distance, which is calculated in azimuthal angle (φ) and in pseudo-rapidity (η), to the jet axis is smaller than the jet resolution parameter R:2 +2 < R
Summary
There are several scenarios proposed to explain this, e.g. collective effects and string fragmentation in a hydrodynamically expanding environment [5]. These collective phenomena [6] are a characteristic feature of the Underlying Event (UE) in Pb–Pb collisions, that are independent of the fragmentation process but could have a possible impact on the jet fragments. Particles with a momentum larger than pT = 4-6 GeV/c would, on the other hand, be produced in hard processes via fragmentation, that does not lead to an enhanced production of baryons (compared to production in vacuum). The study of identified particle yields and ratios like Λ(Λ) and K0S in inclusive production and comparison to production in jets will allow to trace
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