An Insight into Strangeness with ϕ (1020) Production in Small to Large Collision Systems with ALICE at the LHC

Abstract

Hadronic resonances are unique tools to investigate the interplay of re-scattering and regeneration effects in the hadronic phase of heavy-ion collisions. As the ϕ meson has a longer lifetime compared to other resonances, it is expected that its production will not be affected by regeneration and re-scattering processes. Measurements in small collision systems such as proton-proton (pp) collisions provide a necessary baseline for heavy-ion data and help to tune pQCD inspired event generators. Given that the ϕ is a bound state of strange-antistrange quark pair (s s ¯ ), measurements of its production can contribute to the study of strangeness production. Recent results obtained by using the ALICE detector show that although ϕ has zero net strangeness content, it behaves like a particle with open strangeness in small collision systems and the experimental results agree with thermal model predictions in large systems. The production mechanism of ϕ is yet to be understood. We report on measurements with the ALICE detector at the LHC of ϕ meson production in pp, p–Pb, Xe–Xe and Pb–Pb collisions. These results are reported for minimum bias event samples and as a function of the charged-particle multiplicity or centrality. The results include the transverse momentum (pT ) distributions of ϕ as well as the ⟨ pT⟩ and particle yield ratios. The ϕ effective strangeness will be discussed in relation to descriptions of its production mechanism, such as strangeness canonical suppression, non-equilibrium production of strange quarks and thermal models. © 2021, Springer Nature Singapore Pte Ltd.