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arXiv · 1912.03477

Contributions of box diagrams and $Δ(1940)$ resonance to $K^0Σ^+$ photoproduction

Xuyang Liu·Daris Samart·Kai Xu·Ayut Limphirat·Yupeng Yan·Qiang Zhao
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Abstract

We study first the box-diagram contribution to the $γp\,\rightarrow \,K^0Σ^+$ process to understand the anomaly of the kaon photoproduction cross section from CBELSA/TAPS experiment at Electron Stretcher Accelerator (ELSA), where the imaginary part of the scattering amplitude from the box-diagrams is calculated by using Cutkosky's rules in the on-shell approximation while the real part of the amplitude is derived by dispersion relation calculations. Together with the results of the K-MAID model, the contribution of the box-diagrams fails to provide the sudden drop of the differential cross-section between the $K^*\,Λ$ and $K^*\,Σ$ thresholds. In addition, we include the $Δ(1940)$ resonance in the process to complete the description of the differential cross-section. Combining the contributions from the K-MAID model, the box-diagrams and the $Δ(1940)$ resonance, we have obtained the theoretical differential cross-section the $γp\,\rightarrow \,K^0Σ^+$ process, which is compatible with the CBELSA/TAPS experimental data.

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Xuyang Liu, Daris Samart, Kai Xu, Ayut Limphirat, Yupeng Yan, Qiang Zhao. 2019-12-07. Contributions of box diagrams and $Δ(1940)$ resonance to $K^0Σ^+$ photoproduction. https://arxiv.org/abs/1912.03477

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