标题： γγ到ππ的夸克模型计算包括末态相互作用 显示英文标题

标题： A Quark Model Calculation of gamma gamma to pi pi Including Final State Interactions

摘要： 对过程 gamma gamma -> pi+ pi- 和 gamma gamma -> pi0 pi0 进行了夸克模型计算。 在树图层次，只有带电介子与初始状态光子耦合，因此最终态中不应出现中性介子。 然而，观察到一个很小但显著的 gamma gamma -> pi0 pi0 截面。 我们证明这可能由末态相互作用引起的同位旋空间旋转所解释。 得到的 pi+ pi- 截面与实验结果良好一致，而 pi0 pi0 截面与数据定性一致。 显示英文摘要

摘要： A quark model calculation of the processes gamma gamma -> pi+ pi- and gamma gamma -> pi0 pi0 is performed. At tree level, only charged pions couple to the initial state photons and neutral pions are not expected in the final state. However, a small but significant gamma gamma -> pi0 pi0 cross section is observed. We demonstrate that this may be accounted for by a rotation in isospin space induced by final state interactions. The resulting pi+ pi- cross section is in good agreement with experiment while the pi0 pi0 cross section is in qualitative agreement with the data.