# Draw rotated self-energy of electron on an oblique line TikZ-Feynman

I have to draw a diagram for radiative corrections on an external field, but I would like to make half-loops for self-energy of electron on the slanted fermionic lines (see figure and code). I tried this but it doesn't seem to have any effect. There is nothing on the documentation. Could anyone help me?

\begin{tikzpicture}
\begin{feynman}
\vertex (a) ;
\vertex[below right= of a] (b);
\vertex[above right= of b] (c);
\vertex[crossed dot, below= of b] (d) {};
\diagram* {
(a) -- [fermion] (b) -- [fermion] (c);
(b) -- [boson] (d);
};
\draw [boson, half left] ($(b)!0.2!(c)$) -- ($(b)!0.8!(c)$);
\end{feynman}
\end{tikzpicture} Is it possibile to add momentum for this half loop?

EDIT:

https://www.overleaf.com/8134191135krhdbksyvxpg

the idea is to draw these • Please make your code compilable. This is a LaTeX forum, so you should describe what is causing you problems without referring to the physics behind it. You could make a hand drawing of your desired/expected output. Dec 29, 2022 at 18:14
• @hpekristiansen Finally somebody that write "You could make a hand drawing of your desired/expected output." ;-) Dec 29, 2022 at 19:42
• Possibly related since “half loop” is the only thing I understood. Dec 29, 2022 at 22:24
• Maybe also 1 or 2. Dec 29, 2022 at 22:31
• I added the link and the expected output Dec 30, 2022 at 10:20

Instead of using -- to draw a straight path, you could use the tikz arc path:

% !TeX TS-program = lualatex

\documentclass{standalone}

\usepackage{tikz-feynman}

\begin{document}
\begin{tikzpicture}
\begin{feynman}
\vertex (a) ;
\vertex[below right= of a] (b);
\vertex[above right= of b] (c);
\vertex[crossed dot, below= of b] (d) {};
\diagram* {
(a) -- [fermion] (b) -- [fermion] (c);
(b) -- [boson] (d);
};
\draw [boson] ($(b)!0.2!(c)$) arc[start angle=235, end angle=35, radius=12pt] node[midway,above] {k} ($(b)!0.8!(c)$);
\end{feynman}
\end{tikzpicture}
\end{document} • I updated the Overleaf with your code, and I want to use momentum attribute to specify the momentum verse, but I don't understand why appears 3 arrows, instead 1 Dec 30, 2022 at 16:37