A Coupled-channel analysis for phi-photoproduction with Lambda(1520)
A Coupled-channel analysis for phi-photoproduction with Lambda(1520)
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DOI：
10.1103/physrevc.81.059901
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发表时间：
2009-05
影响因子：
3.1
通讯作者：
S. Ozaki;O. Scholten;A. Hosaka;H. Nagahiro
中科院分区：
文献类型：
--
作者：
S. Ozaki;O. Scholten;A. Hosaka;H. Nagahiro
我们用基于K矩阵的耦合通道有效拉格朗日方法研究了质子的光产生。由于$K\Lambda(1520)$通道的阈值能量接近于$\Phi N$的阈值能量，因此该通道对阈值能区附近的光产生的贡献可能会产生一些意想不到的结构。在跃迁幅度$K\Lambda(1520)\到\Phi N$中，运动学允许中间介子在壳层上。这发生在能区，在那里已经观察到峰值结构的$\Phi$-光产生。然而，在我们的计算中，壳层上的Kaon效应确实复制了一个峰结构，其量级太小，无法解释观察到的效应。作为下一步，我们在我们的模型中引入核子共振。如果共振包含显性的隐藏奇异性分量，则共振与$K\Lambda(1520)$和$\Phi N$通道的耦合不受Ozi规则的抑制。我们发现，在合适的能量下，共振可以重现正确量级的峰结构。我们还研究了耦合通道和共振对光生电子的角分布和自旋密度矩阵的影响。
We investigate photoproduction of $\phi$-mesons off protons within a coupled-channel effective-Lagrangian method which is based on the K-matrix approach. Since the threshold energy of the $K\Lambda(1520)$ channel is close to that of $\phi N$, the contribution of this channel to $\phi$-photoproduction near the threshold energy region may give rise to some unexpected structures. In the transition amplitude $K\Lambda(1520) \to \phi N$, the kinematics allows an intermediate kaon to be on-shell. This happens in the energy region where a peak structure has been observed in $\phi$-photoproduction. In our calculations the on-shell kaon effect indeed reproduces a peak structure, however, with a magnitude that is far too small to explain the observed effect. As a following step we introduce a nucleon resonance in our model. The coupling of the resonance to the $K\Lambda(1520)$ and $\phi N$ channels is not suppressed by the OZI rule if the resonance contains a dominant hidden strangeness component. We find that the resonance can reproduce a peak structure of the correct magnitude at the right energy. We also investigate the effects of coupled channels and the resonance on the angular distribution and the spin density matrices for $\phi$ photoproduction.