A unified approach for the hadronic weak decays of $Λ$ and $Σ^{\pm}\to Nπ$
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| Format: | Preprint |
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2025
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| _version_ | 1866915668407877632 |
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| author | Cao, Ye Duan, Ming-Xiao Tao, Zhong Zhao, Qiang |
| author_facet | Cao, Ye Duan, Ming-Xiao Tao, Zhong Zhao, Qiang |
| contents | We provide a unified approach for the two-body hadronic weak decays of hyperons with $S=-1$, i.e. $Λ$ and $Σ^\pm$, in the framework of the non-relativistic constitute quark model (NRCQM). A combined analysis shows that the branching ratios and asymmetry parameters of the decay channels $Λ\to pπ^-$ and $Σ^\pm\to Nπ$ can be well described in the same framework with the direct pion emission, color suppressed internal $W$ emission, and pole terms included. However, the channel $Λ\to nπ^0$ indicates significant deviations from the experimental data based on these mentioned transition mechanism. We demonstrate that the final state interactions (FSIs) via the coupled-channel rescatterings play a crucial role in $Λ\to nπ^0$. Namely, the dominant decay channel of $Λ\to pπ^-$ can contribute to $Λ\to nπ^0$ via the $pπ^-\to nπ^0$ rescatterings. This is a leading correction effect for $Λ\to nπ^0$ at the one-loop level. We find that such FSIs only become the leading effects in $Λ\to nπ^0$, but contribute as subleading contributions in other channels. We also demonstrate that the pole terms are indispensable in these hyperon decays. In particular, for $Σ^-\to nπ^-$ and $Σ^+\to nπ^+$, it shows that $Λ(1405)$ as the intermediate state in the pole term amplitude is necessary for reproducing the experimental data. We also find that a dynamic selection rule forbids the radial excitation state $N(1710)$ of the quark model multiplet $|70, ^28,2,0^+,1/2^+\rangle$ from contribution. To some extent, the hyperon hadronic weak decays serve as a special probe for the underlying transition mechanisms and can provide some constraints on the intermediate $J^P=1/2^\pm$ baryon resonances. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2512_10346 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | A unified approach for the hadronic weak decays of $Λ$ and $Σ^{\pm}\to Nπ$ Cao, Ye Duan, Ming-Xiao Tao, Zhong Zhao, Qiang High Energy Physics - Phenomenology High Energy Physics - Experiment Nuclear Theory We provide a unified approach for the two-body hadronic weak decays of hyperons with $S=-1$, i.e. $Λ$ and $Σ^\pm$, in the framework of the non-relativistic constitute quark model (NRCQM). A combined analysis shows that the branching ratios and asymmetry parameters of the decay channels $Λ\to pπ^-$ and $Σ^\pm\to Nπ$ can be well described in the same framework with the direct pion emission, color suppressed internal $W$ emission, and pole terms included. However, the channel $Λ\to nπ^0$ indicates significant deviations from the experimental data based on these mentioned transition mechanism. We demonstrate that the final state interactions (FSIs) via the coupled-channel rescatterings play a crucial role in $Λ\to nπ^0$. Namely, the dominant decay channel of $Λ\to pπ^-$ can contribute to $Λ\to nπ^0$ via the $pπ^-\to nπ^0$ rescatterings. This is a leading correction effect for $Λ\to nπ^0$ at the one-loop level. We find that such FSIs only become the leading effects in $Λ\to nπ^0$, but contribute as subleading contributions in other channels. We also demonstrate that the pole terms are indispensable in these hyperon decays. In particular, for $Σ^-\to nπ^-$ and $Σ^+\to nπ^+$, it shows that $Λ(1405)$ as the intermediate state in the pole term amplitude is necessary for reproducing the experimental data. We also find that a dynamic selection rule forbids the radial excitation state $N(1710)$ of the quark model multiplet $|70, ^28,2,0^+,1/2^+\rangle$ from contribution. To some extent, the hyperon hadronic weak decays serve as a special probe for the underlying transition mechanisms and can provide some constraints on the intermediate $J^P=1/2^\pm$ baryon resonances. |
| title | A unified approach for the hadronic weak decays of $Λ$ and $Σ^{\pm}\to Nπ$ |
| topic | High Energy Physics - Phenomenology High Energy Physics - Experiment Nuclear Theory |
| url | https://arxiv.org/abs/2512.10346 |