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
Abstract
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
JUFO rating: 2