答案1
默认情况下,TikZ-Feynman
命令使用弹簧布局算法来放置所有边。您的图表需要手动放置每个顶点。
\documentclass[border=10]{standalone}
\usepackage{tikz}
\usepackage{tikz-feynman}
\begin{document}
\begin{tikzpicture}
\begin{feynman}
\vertex (a);
\vertex[right=of a] (b);
\vertex[below right=of a] (f1);
\vertex[above right=of a] (f2);
\diagram*{
(a) -- [photon, edge label=\(\gamma\)] (b),
(a) -- [fermion, edge label'=\(e^-\)] (f1),
(a) -- [anti fermion, edge label=\(e^+\)] (f2),
};
\end{feynman}
\end{tikzpicture}
\begin{tikzpicture}
\begin{feynman}
\vertex (a);
\vertex[right=of a] (b);
\vertex[above left=of b] (f1);
\vertex[above right=of b] (f2);
\diagram*{
(a) -- [photon, edge label'=\(\gamma\)] (b),
(b) -- [anti fermion, edge label'=\(e^-\)] (f1),
(b) -- [fermion, edge label'=\(e^-\)] (f2),
};
\end{feynman}
\end{tikzpicture}
\begin{tikzpicture}
\begin{feynman}
\vertex (a);
\vertex[right=of a] (b);
\vertex[below right=of b] (f1);
\vertex[above right=of b] (f2);
\diagram*{
(a) -- [photon, edge label=\(\gamma\)] (b),
(b) -- [anti fermion, edge label'=\(e^+\)] (f1),
(b) -- [fermion, edge label'=\(e^-\)] (f2),
};
\end{feynman}
\end{tikzpicture}
\end{document}