Feynman diagram using tikz

Question

I am trying to write a code to produce a Feynman diagram as given below.

The code I have written down so far is this.

\feynmandiagram [vertical=f1 to f2] {
  anu [particle=\(\overline{\chi}\)] -- [fermion] b [blob],
  nu  [particle=\(\chi\)] -- [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,
};

So far no luck! I am not sure whether this diagram is produced in LaTeX or not! In any case can anyone guide me on how can I produce it in LaTeX? Thanks in advance.

If I wrap your code fragment into \documentclass[tikz,border=3mm]{standalone} \usepackage{tikz-feynman} \begin{document} and \end{document} and compile it with lualatex, I get a diagram. Can you clarify your question? Do you want this very output, with the arrows of varying line width, or just the topology of the screen shot? — , Mar 28 '20 at 18:41
@Schrödinger's cat-This is exactly what I am looking for. The code that represents the same topology as the diagram. — Mass, Mar 28 '20 at 18:45

score 2 · Accepted Answer · 2020-03-28T19:59:09.007

I do not think that the layout algorithms employed by tikz-feynman are great for this diagram, so here manual relative placement is used. (The diagram is also not entirely correct: on the bottom right a fermion turns into two fermions, which is impossible.)

\documentclass[tikz,border=3mm]{standalone}
\usepackage{tikz-feynman}
\usetikzlibrary{decorations.pathreplacing,calligraphy}
\begin{document}
\begin{tikzpicture} 
\begin{feynman}
\vertex (chi1) {\(\chi\)}; 
\vertex[below=of chi1] (chi2) {\(\overline{\chi}\)}; 
\path (chi1) -- (chi2) node[midway,right=4em,blob] (blob);
\vertex[right=10em of chi1] (f1) {$W^-/Z/q$};
\vertex[right=10em of chi2] (f2)  {$W^+/Z/\bar q$};
\draw[thick,decorate,
    decoration={calligraphic brace,amplitude=3pt,raise=0.1ex}] 
 (f1.north east) -- (f2.south east) coordinate[midway,right=1.2em](m0);
\path ([xshift=2ex]f1.east) coordinate(t0) ++ (45:1) coordinate (t1) 
 ++ (60:1) coordinate[label={[anchor=240]$\gamma$}] (t2)
(t1)  ++ (30:1) coordinate[label={[anchor=210]$\gamma$}]  (t3)
(m0) ++ (0:1) coordinate (m1) (m1) ++ (15:1)
coordinate[label={[anchor=195]$\nu_\mu$}] (m2) 
(m1) ++ (-15:1) coordinate (m3) ++ (0:1) coordinate[label=right:$\nu_e$]  (m4)
(m3) ++ (-30:1) coordinate[label={[anchor=150]$e^+$}]  (m5)
([xshift=2ex]f2.east) coordinate(b0) ++ (-45:1) coordinate (b1)  
++ (00:1) coordinate[label=right:$\bar\nu_\mu$] (b2)
(b1)  ++ (-45:1) coordinate (b3) -- ++ (0:1) coordinate[label=right:$\nu_\mu$] (b4)
(b3) -- ++ (-30:1) coordinate[label={[anchor=150]$\bar\nu_e$}] (b6)
(b3) -- ++ (-60:1) coordinate[label={[anchor=120]$e^-$}] (b5);
\diagram*{
(chi1)-- [fermion] (blob), (blob)-- [fermion] (chi2),
(f2)-- [fermion] (blob), (blob)-- [fermion] (f1),
(t0) --[scalar,edge label=$\pi^0$] (t1) -- [photon] (t2), 
(t1) -- [photon] (t3),
(m0) --[scalar,edge label=$\pi^+$] (m1) -- [fermion] (m2), 
(m1) -- [anti fermion,edge label'=$\mu^+$] (m3) -- [fermion] (m4),
(m3) -- [anti fermion] (m5),
(b0) --[scalar,edge label'=$\pi^-$] (b1) -- 
[anti fermion] (b2), 
(b1) -- [fermion,edge label'=$\mu^-$] (b3) --[fermion] (b5),
(b3) --[fermion] (b4),
(b3) --[anti fermion] (b6),
}; 
\end{feynman}
\end{tikzpicture}
\end{document}

Changing the propagators to become arrows of varying line width would be relatively easy.

thank you. How can I site your contribution? Please let me know. — Mass, Mar 28 '20 at 20:04
@ams No need. I was always excited about the American Marmot Society, so I am glad to help. ;-) — , Mar 28 '20 at 20:05

Feynman diagram using tikz

1 Answers1