# Drawing specific Feynman diagram with TikZ

I would like to draw the Feynman diagram shown in the picture below with TikZ.

Edit: The code I have so far is

\tikzfeynmanset{
every vertex/.style={red, dot},
every blob/.style={draw=green!40!black, pattern color=green!40!black},
every crossed dot/.style={blue},
}
\begin{tikzpicture}
\begin{feynman}
\vertex (a) {$$\nu$$};
\vertex [below right=of a] (b);
\vertex [below left=of b] (f1) {$$\bar{\nu}$$};
\vertex [above right=of b] (f2);
\vertex [below right=of b] (f3);
\diagram* {
(a) -- [fermion] (b)[blob] -- [fermion] (f1),
(b) -- [anti fermion,bend left,edge label=$$\bar{\nu}$$] (f2)[crossed dot],
(b) -- [anti fermion,bend left,edge label=$$\bar{\nu}$$] (f3)[crossed dot],
(b) -- [fermion,bend right,edge label'=$$\nu$$] (f2)[crossed dot],
(b) -- [fermion,bend right,edge label'=$$\nu$$] (f3)[crossed dot]
};
\end{feynman}
\end{tikzpicture}


However, where the blob and the crossed dots should be, there are still simple vertices. How can I implement the blob and the two "condensate" vertices? Thanks for your help! • Neutrino - pair annihilation? – user31729 Feb 2 '16 at 16:04
• The blob is an instanton, the crosses are condensates. – Thomas Feb 2 '16 at 16:05
• Suggest you both search this site for "feynman diagram" as there are nearly 100 results. A useful one could be tex.stackexchange.com/questions/22622/…. And there is a nice Feynman example in this gallery texample.net/tikz/examples/area/physics – R. Schumacher Feb 2 '16 at 16:10
• I know how to draw simple Feynman diagrams, but I haven't found this specific one anywhere. – Thomas Feb 2 '16 at 16:29
• Since you already know how to draw simple diagrams, can you post same sample code of where exactly are you stuck? In any case, the commented examples in github.com/fliptanedo/tikzfeynman.sty might help you. – Jonas Malaco Feb 2 '16 at 17:02

## 1 Answer

Use the "invisible edges" strategy suggested in tikz-feynman manual. Compile with LuaLaTeX

\documentclass[tikz]{standalone}
\usepackage{tikz-feynman}
\begin{document}
\feynmandiagram [vertical=f1 to f2] {
anu [particle=$$\overline{\nu}$$] -- [fermion] b [blob],
nu  [particle=$$\nu$$] -- [fermion] b,
b   -- [fermion,bend right=10,edge label'=$$\nu$$] f1 [crossed dot],
b   -- [fermion,bend left=10,edge label=$$\overline{\nu}$$] f1,
b   -- [fermion,bend right=10,edge label'=$$\nu$$] f2 [crossed dot],
b   -- [fermion,bend left=10,edge label=$$\overline{\nu}$$] f2,
% In the picture below I used "[opacity=0.2]" in place of "[draw=none]" to
% show where the edges are.
nu  -- [draw=none] anu,
f1  -- [draw=none] f2,
};
\end{document} • Thanks for your answer, but I get an error when compiling it with LuaLaTex: ! LuaTeX error ./tikzfeynman.patch.lua:966: unknown phase – Thomas Feb 3 '16 at 8:55
• Which version of the package do you have? How did you install it? – giordano Feb 3 '16 at 9:05
• It's the current version v1.0.0 downloaded here. I put the .sty file into the folder where I have my .tex document, that's it. When I compile the version you can see in my edit, everything works perfectly fine. – Thomas Feb 3 '16 at 10:54
• The package is on CTAN, you can install from your package manager. That's what I'm using. – giordano Feb 3 '16 at 10:55
• I updated all packages, and finally all your versions work - thanks a lot for your help! – Thomas Feb 3 '16 at 13:56