$$\varLambda (1405)$$ Λ ( 1405 ) mediated triangle singularity in the $$K^-d\rightarrow p\varSigma ^-$$ K - d → p Σ - reaction
Abstract We study for the first time the $$p\varSigma ^-\rightarrow K^-d$$ p Σ - → K - d and $$K^-d\rightarrow p\varSigma ^-$$ K - d → p Σ - reactions close to threshold and show that they are driven by a triangle mechanism, with the $$\varLambda (1405)$$ Λ ( 1405 ) , a proton and a neutron as inter...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2022-11-01
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| Series: | European Physical Journal C: Particles and Fields |
| Online Access: | https://doi.org/10.1140/epjc/s10052-022-10985-8 |
| _version_ | 1798016751144796160 |
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| author | A. Feijoo R. Molina L. R. Dai Eulogio Oset |
| author_facet | A. Feijoo R. Molina L. R. Dai Eulogio Oset |
| author_sort | A. Feijoo |
| collection | DOAJ |
| description | Abstract We study for the first time the $$p\varSigma ^-\rightarrow K^-d$$ p Σ - → K - d and $$K^-d\rightarrow p\varSigma ^-$$ K - d → p Σ - reactions close to threshold and show that they are driven by a triangle mechanism, with the $$\varLambda (1405)$$ Λ ( 1405 ) , a proton and a neutron as intermediate states, which develops a triangle singularity close to the $${\bar{K}}d$$ K ¯ d threshold. We find that a mechanism involving virtual pion exchange and the $$K^-p\rightarrow \pi ^+\varSigma ^-$$ K - p → π + Σ - amplitude dominates over another one involving kaon exchange and the $$K^-p\rightarrow K^-p$$ K - p → K - p amplitude. Moreover, of the two $$\varLambda (1405)$$ Λ ( 1405 ) states, the one with higher mass around 1420 MeV, gives the largest contribution to the process. We show that the cross section, well within measurable range, is very sensitive to different models that, while reproducing $${\bar{K}}N$$ K ¯ N observables above threshold, provide different extrapolations of the $${\bar{K}}N$$ K ¯ N amplitudes below threshold. The observables of this reaction will provide new constraints on the theoretical models, leading to more reliable extrapolations of the $${\bar{K}}N$$ K ¯ N amplitudes below threshold and to more accurate predictions of the $$\varLambda (1405)$$ Λ ( 1405 ) state of lower mass. |
| first_indexed | 2024-04-11T15:55:46Z |
| format | Article |
| id | doaj.art-7372d9e868754a66a05bdbdc1aa942a8 |
| institution | Directory Open Access Journal |
| issn | 1434-6052 |
| language | English |
| last_indexed | 2024-04-11T15:55:46Z |
| publishDate | 2022-11-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | European Physical Journal C: Particles and Fields |
| spelling | doaj.art-7372d9e868754a66a05bdbdc1aa942a82022-12-22T04:15:10ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60522022-11-01821111610.1140/epjc/s10052-022-10985-8$$\varLambda (1405)$$ Λ ( 1405 ) mediated triangle singularity in the $$K^-d\rightarrow p\varSigma ^-$$ K - d → p Σ - reactionA. Feijoo0R. Molina1L. R. Dai2Eulogio Oset3Departamento de Física Teórica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigación de PaternaDepartamento de Física Teórica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigación de PaternaSchool of Science, Huzhou UniversityDepartamento de Física Teórica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigación de PaternaAbstract We study for the first time the $$p\varSigma ^-\rightarrow K^-d$$ p Σ - → K - d and $$K^-d\rightarrow p\varSigma ^-$$ K - d → p Σ - reactions close to threshold and show that they are driven by a triangle mechanism, with the $$\varLambda (1405)$$ Λ ( 1405 ) , a proton and a neutron as intermediate states, which develops a triangle singularity close to the $${\bar{K}}d$$ K ¯ d threshold. We find that a mechanism involving virtual pion exchange and the $$K^-p\rightarrow \pi ^+\varSigma ^-$$ K - p → π + Σ - amplitude dominates over another one involving kaon exchange and the $$K^-p\rightarrow K^-p$$ K - p → K - p amplitude. Moreover, of the two $$\varLambda (1405)$$ Λ ( 1405 ) states, the one with higher mass around 1420 MeV, gives the largest contribution to the process. We show that the cross section, well within measurable range, is very sensitive to different models that, while reproducing $${\bar{K}}N$$ K ¯ N observables above threshold, provide different extrapolations of the $${\bar{K}}N$$ K ¯ N amplitudes below threshold. The observables of this reaction will provide new constraints on the theoretical models, leading to more reliable extrapolations of the $${\bar{K}}N$$ K ¯ N amplitudes below threshold and to more accurate predictions of the $$\varLambda (1405)$$ Λ ( 1405 ) state of lower mass.https://doi.org/10.1140/epjc/s10052-022-10985-8 |
| spellingShingle | A. Feijoo R. Molina L. R. Dai Eulogio Oset $$\varLambda (1405)$$ Λ ( 1405 ) mediated triangle singularity in the $$K^-d\rightarrow p\varSigma ^-$$ K - d → p Σ - reaction European Physical Journal C: Particles and Fields |
| title | $$\varLambda (1405)$$ Λ ( 1405 ) mediated triangle singularity in the $$K^-d\rightarrow p\varSigma ^-$$ K - d → p Σ - reaction |
| title_full | $$\varLambda (1405)$$ Λ ( 1405 ) mediated triangle singularity in the $$K^-d\rightarrow p\varSigma ^-$$ K - d → p Σ - reaction |
| title_fullStr | $$\varLambda (1405)$$ Λ ( 1405 ) mediated triangle singularity in the $$K^-d\rightarrow p\varSigma ^-$$ K - d → p Σ - reaction |
| title_full_unstemmed | $$\varLambda (1405)$$ Λ ( 1405 ) mediated triangle singularity in the $$K^-d\rightarrow p\varSigma ^-$$ K - d → p Σ - reaction |
| title_short | $$\varLambda (1405)$$ Λ ( 1405 ) mediated triangle singularity in the $$K^-d\rightarrow p\varSigma ^-$$ K - d → p Σ - reaction |
| title_sort | varlambda 1405 λ 1405 mediated triangle singularity in the k d rightarrow p varsigma k d p σ reaction |
| url | https://doi.org/10.1140/epjc/s10052-022-10985-8 |
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