Strange hadron collectivity in pPb and PbPb collisions

Abstract

The collective behavior of K${}_{\mathrm{S}}^0$ and $\Lambda /\bar{\Lambda }$ strange hadrons is studied by measuring the elliptic azimuthal anisotropy ($v_2$) using the scalar-product and multiparticle correlation methods. Proton-lead (pPb) collisions at a nucleon-nucleon center-of-mass energy $\sqrt{s_{\mathrm{NN}}}$ = 8.16 TeV and lead-lead (PbPb) collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV collected by the CMS experiment at the LHC are investigated. Nonflow effects in the pPb collisions are studied by using a subevent cumulant analysis and by excluding events where a jet with transverse momentum greater than 20\GeV is present. The strange hadron $v_2$ values extracted in \pPb collisions via the four- and six-particle correlation method are found to be nearly identical, suggesting the collective behavior. Comparisons of the pPb and PbPb results for both strange hadrons and charged particles illustrate how event-by-event flow fluctuations depend on the system size.

Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/HIN-19-004 (CMS Public Pages)

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Cited by in corpus (2)

• Observation of $\Lambda$ hyperon local polarization in pPb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 8.16 TeV
• Observation of long-range collective flow in OO and NeNe collisions and implications for nuclear structure studies