论文标题
$ ep \ ep \ rightarrowenπ^+$在小$ -t $的$ ep \ rightarrowenπ^+$与hadronic模型和分散关系方法
Two-Photon-Exchange effect in $ep\rightarrow enπ^+$ at small $-t$ with the hadronic model and dispersion relation approach
论文作者
论文摘要
在这项工作中，讨论了$ ep \ rightarrowenπ^+$在小$ -t $中的$ ep \ rightarrowenπ+$中的两光量 - 交换（TPE）效应。在先前的工作中，在pion占优势近似值下，在数值中估计了具有$π$中间状态的TPE贡献。在这里，我们将讨论扩展到包括一个$ρ$中级状态。 TPE贡献可以通过一个标量函数在限制$ m_e \ rightarrow 0 $中描述，分析了该标量函数满足的分散关系（DR）。在HADRONIC模型中给出了TPE贡献的假想部分的分析表达式。结合了这些分析表达式和DR，可以在任何可用区域轻松估算TPE贡献的相应实际部分。这可以帮助进一步的实验分析以方便的方式包括TPE贡献。数字结果表明，具有一个$ρ$中间状态的TPE校正远小于当前能量区域中一个$π$中间状态的TPE校正。这些结果表明，具有弹性状态的TPE贡献是$ ep \ rightArrowenπ^+$在小$ -t $中的主要TPE贡献。
In this work, the two-photon-exchange (TPE) effect in $ep\rightarrow enπ^+$ at small $-t$ is discussed. In the previous work, the TPE contribution with one $π$ intermediate state is estimated numerically within a hadronic model under the pion-dominance approximation. Here we extend the discussion to include one $ρ$ intermediate state. The TPE contribution can be described by one scalar function in the limit $m_e\rightarrow 0$, the dispersion relation (DR) satisfied by this scalar function is analysed. The analytic expressions for the imaginary parts of the TPE contributions from one $π$ or one $ρ$ intermediate state are given within the hadronic model. Combining these analytic expressions and the DR, the corresponding real parts of the TPE contributions can be estimated easily at any available region. This can help the further experimental analysis to include the TPE contributions in a convenient way. The numeric results show that the TPE correction with one $ρ$ intermediate state is much smaller than that with one $π$ intermediate state in the current energy region. These results suggest that the TPE contribution with an elastic state is the main TPE contribution in $ep\rightarrow enπ^+$ at small $-t$.
