I am trying to make the following disconnected diagram using tikz-feynman
My attempt:
\documentclass{standalone}
\usepackage[compat=1.1.0]{tikz-feynman}
\begin{document}
\begin{tikzpicture}
\begin{feynman}[large]
\vertex [anchor = north](a) {$t'$};
\vertex [anchor = north, right = of a] (b) {$t$};
\vertex (d) at ($(a)!0.5!(b)$);
\vertex [small, dot, below = of d] (c) {};
\diagram*{(a) --[fermion] (b),
(c) -- [fermion,loop, in = 45, out = 135, min distance = 1cm] (c) -- [fermion,loop, out = -45, in = -135, min distance = 1cm] (c)};
\end{feynman}
\end{tikzpicture}
\end{document}
This produces the following output
As you can see, the fermion loops do not show up! Why is that, and how can i fix this?
Thank you.