A1 Journal article (refereed)
Exploring the NΛ–NΣ coupled system with high precision correlation techniques at the LHC (2022)

ALICE Collaboration. (2022). Exploring the NΛ–NΣ coupled system with high precision correlation techniques at the LHC. Physics Letters B, 833, Article 137272. https://doi.org/10.1016/j.physletb.2022.137272

JYU authors or editors

Publication details

All authors or editors: ALICE Collaboration

Journal or series: Physics Letters B

ISSN: 0370-2693

eISSN: 1873-2445

Publication year: 2022

Publication date: 04/07/2022

Volume: 833

Article number: 137272

Publisher: Elsevier BV

Publication country: Netherlands

Publication language: English

DOI: https://doi.org/10.1016/j.physletb.2022.137272

Publication open access: Openly available

Publication channel open access: Open Access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/82960

Web address of parallel published publication (pre-print): https://arxiv.org/abs/2104.04427


The interaction of Λ and Σ hyperons (Y) with nucleons (N) is strongly influenced by the coupled-channel dynamics. Due to the small mass difference of the NΛ and NΣ systems, the coupling strength of the NΣ↔NΛ processes is non-negligible and constitutes a crucial element in the determination of the NΛ interaction. In this letter we present the most precise measurements on the interaction of pΛ pairs, from zero relative momentum up to the opening of the NΣ channel. The correlation function in the relative momentum space for pΛ⊕p¯¯¯Λ¯¯¯¯ pairs measured in high-multiplicity triggered pp collisions at s√ = 13 TeV at the LHC is reported. The opening of the inelastic NΣ channels is visible in the extracted correlation function as a cusp-like structure occurring at relative momentum k∗ = 289 MeV/c. This represents the first direct experimental observation of the NΣ→NΛ coupled channel in the pΛ system. The correlation function is compared with recent chiral effective field theory calculations, based on different strengths of the NΣ↔NΛ transition potential. A weaker coupling, as possibly supported by the present measurement, would require a more repulsive three-body NNΛ interaction for a proper description of the Λ in-medium properties, which has implications on the nuclear equation of state and for the presence of hyperons inside neutron stars.

Keywords: particle physics; nuclear physics

Contributing organizations

Ministry reporting: Yes

Reporting Year: 2022

Preliminary JUFO rating: 2

Last updated on 2023-10-01 at 14:25