A1 Journal article (refereed)
ΛK femtoscopy in Pb-Pb collisions at √sNN = 2.76 TeV (2021)

ALICE Collaboration. (2021). ΛK femtoscopy in Pb-Pb collisions at √sNN = 2.76 TeV. Physical Review C, 103(5), Article 055201. https://doi.org/10.1103/PhysRevC.103.055201

JYU authors or editors

Publication details

All authors or editors: ALICE Collaboration

Journal or series: Physical Review C

ISSN: 2469-9985

eISSN: 2469-9993

Publication year: 2021

Volume: 103

Issue number: 5

Article number: 055201

Publisher: American Physical Society

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1103/PhysRevC.103.055201

Publication open access: Openly available

Publication channel open access: Partially open access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/76409

Web address of parallel published publication (pre-print): https://arxiv.org/abs/2005.11124

Abstract

The first measurements of the scattering parameters of ΛK pairs in all three charge combinations (ΛK+, ΛK−, and ΛK0S) are presented. The results are achieved through a femtoscopic analysis of ΛK correlations in Pb-Pb collisions at √sNN=2.76 TeV recorded by ALICE at the Large Hadron Collider. The femtoscopic correlations result from strong final-state interactions and are fit with a parametrization allowing for both the characterization of the pair emission source and the measurement of the scattering parameters for the particle pairs. Extensive studies with the THERMINATOR 2 event generator provide a good description of the nonfemtoscopic background, which results mainly from collective effects, with unprecedented precision. Furthermore, together with HIJING simulations, this model is used to account for contributions from residual correlations induced by feed-down from particle decays. The extracted scattering parameters indicate that the strong force is repulsive in the ΛK+ interaction and attractive in the ΛK− interaction. The data hint that the ΛK0S interaction is attractive; however, the uncertainty of the result does not permit such a decisive conclusion. The results suggest an effect arising either from different quark-antiquark interactions between the pairs (s¯s in ΛK+ and u¯u in ΛK−) or from different net strangeness for each system (S=0 for ΛK+, and S=−2 for ΛK−). Finally, the ΛK systems exhibit source radii larger than expected from extrapolation from identical particle femtoscopic studies. This effect is interpreted as resulting from the separation in space-time of the single-particle Λ and K source distributions.

Keywords: particle physics

Contributing organizations

Ministry reporting: Yes

Reporting Year: 2021

JUFO rating: 2