标题： 光生$γp \to f_0(980) p$在有效拉格朗日方法中的研究 显示英文标题

标题： Photoproduction $γp \to f_0(980) p$ in an effective Lagrangian approach

摘要： 最近关于微分截面和光子束不对称性$\Sigma$的数据，来自 LEPS2/BGOegg 合作组对于$\gamma p \to f_0(980) p$反应的分析是在树级有效拉格朗日方法中进行的。 在构建反应振幅以再现数据时，考虑了$t$通道的$\rho$和$\omega$交换，$u$和$s$通道的$N$交换，相互作用电流以及可能的$s$通道的$N^*$交换。 结果表明，为了描述LEPS2/BGOegg数据，必须考虑在$s$通道中来自$N(2040)3/2^+$或$N(2100)1/2^+$共振交换的贡献，并且它们主导了$\gamma p \to f_0(980) p$的微分截面。 进一步分析表明，来自$t$-通道$\rho$和$\omega$交换以及相互作用电流对微分截面和光束不对称性的贡献相对较小，而来自$u$-通道$N$交换的贡献在模型中包含$N(2040)3/2^+$时是显著的，而在模型中包含$N(2100)1/2^+$时则可以忽略。 目标不对称性的预测$T$对于$\gamma p \to f_0(980) p$给出，这可以通过未来实验进行检验。 显示英文摘要

摘要： The most recent data on differential cross sections and photon beam asymmetries $\Sigma$ from the LEPS2/BGOegg Collaboration for the $\gamma p \to f_0(980) p$ reaction are analyzed within a tree-level effective Lagrangian approach. The $t$-channel $\rho$ and $\omega$ exchanges, the $u$- and $s$-channel $N$ exchanges, the interaction current, and the possible $s$-channel $N^*$ exchanges are taken into account in constructing the reaction amplitudes to reproduce the data. The results show that the contributions from either the $N(2040)3/2^+$ or the $N(2100)1/2^+$ resonance exchange in the $s$ channel are necessarily required to describe the LEPS2/BGOegg data and they dominate the differential cross sections of $\gamma p \to f_0(980) p$. Further analysis shows that the contributions from the $t$-channel $\rho$ and $\omega$ exchanges and the interaction current are rather small to both differential cross sections and photo beam asymmetries, and the contributions from $u$-channel $N$ exchange are considerable in the case of including $N(2040)3/2^+$ in the model while negligible in the case of including $N(2100)1/2^+$ in the model. Predictions of target asymmetries $T$ for $\gamma p \to f_0(980) p$ are given, which can be examined by future experiments.