Triangle singularity in the K.sup.−./sup.d → pΣ.sup.−./sup. reaction and its relevance to find the K̅N amplitude below threshold

0568505 - ÚJF 2023 RIV FR eng C - Conference Paper (international conference)
Oset, E. - Molina, R. - Dai, L. - Feijoo, Aliau Eduardo Alberto
Triangle singularity in the K⁻d → pΣ⁻ reaction and its relevance to find the K̅N amplitude below threshold.
EPJ Web of Conferences. Vol. 271. Les Ulis: EDP Science, 2022, č. článku 07006. E-ISSN 2100-014X.
[14th International Conference on Hypernuclear and Strange Particle Physics (HYP2022). Prague (CZ), 27.06.2022-01.07.2022]
R&D Projects: GA ČR GA19-19640S
Institutional support: RVO:61389005
Keywords : reversal reaction * Lambda(1405)
OECD category: Nuclear physics
https://doi.org/10.1051/epjconf/202227107006

We study for the first time the pΣ− → K−d and its time reversal reaction close to threshold and show that they are driven by a triangle mechanism, with the Λ(1405), a proton and a neutron as intermediate states, which develops a triangle singularity close to the K̅d threshold. As the main result, we find that the cross section, well within measurable range, is very sensitive to different models that, while reproducing K̅N observables above threshold, provide different extrapolations of the K̅N amplitudes below threshold. The observables of this reaction will provide new constraints on the theoretical models, leading to more reliable extrapolations of the K̅N amplitudes below threshold and to more accurate predictions of the Λ(1405) state of lower mass.
Permanent Link: https://hdl.handle.net/11104/0339808