An insight into strangeness with $\varphi$(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 $\varphi$ 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 $\varphi$ is a bound state of strange-antistrange quark pair (s$\bar{\mathrm{s}}$), measurements of its production can contribute to the study of strangeness production. Recent results obtained by using the ALICE detector show that although $\varphi$ 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 $\varphi$ is yet to be understood. We report on measurements with the ALICE detector at the LHC of $\varphi$ 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 ($p_{\mathrm{T}}$) distributions of $\varphi$ as well as the $⟨p_{\mathrm{T}}⟩$ and particle yield ratios. The $\varphi$ 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.

6 pages, 6 captioned figures, conference proceedings (23rd DAE-BRNS High Energy Physics Symposium 2018)

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