Abstract In this paper, we study the polarization of the Λ ( 1405 ) in the γ p → K + π Σ reaction within an effective Lagrangian approach and isobar model. In our model, the Λ ( 1405 ) is excited through the t-channel K / K ⁎ exchanges and u-channel hyperon exchange. Compared to previous studies, we also include the contribution from a contact term, which is necessary for our model to interpret the polarization of the Λ ( 1405 ) . In addition, we also discuss the possibility to verify the proposed two-pole structure of the Λ ( 1405 ) using the polarization data. We find that the polarization of the Λ ( 1405 ) or the polarization of the final Σ in this reaction is sensitive to the invariant mass M π Σ . Thus the measurement of the dependence of the Λ ( 1405 ) polarization on the M π Σ can offer valuable information about the pole structure of the Λ ( 1405 ) .

中文翻译：

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γp → K+πΣ 反应中 Λ(1405) 的极化

摘要 在本文中，我们在有效的拉格朗日方法和等压线模型中研究了 γ p → K + π Σ 反应中 Λ ( 1405 ) 的极化。在我们的模型中，Λ (1405) 通过 t 通道 K / K ⁎ 交换和 u 通道超子交换被激发。与之前的研究相比，我们还包括了接触项的贡献，这对于我们的模型解释 Λ (1405) 的极化是必要的。此外，我们还讨论了使用极化数据验证 Λ (1405) 提出的两极结构的可能性。我们发现 Λ (1405) 的极化或该反应中最终 Σ 的极化对不变质量 M π Σ 很敏感。