% !TEX program = pdflatexmk
% !TEX parameter = -shell-escape
% Author: Izaak Neutelings (December 24)
% Instructions: To compile via command line, run the following twice
%   pdflatex -shell-escape extract/ttbarV$TAG.tex
\documentclass[11pt,border=4pt]{standalone}
\usepackage{feynmp-auto}
\begin{document}
\begin{fmffile}{feyngraph}
  \fmfframe(-10,14)(7,16){ % padding (L,T)(R,B)
  \begin{fmfgraph*}(120,75) % dimensions (WH)
    % line style
    \fmfset{wiggly_len}{12} % boson wavelength
    \fmfset{wiggly_slope}{65} % boson slope of waves
    % external vertices
    \fmfleft{i2,i1}
    \fmfright{o2,oV,o1}
    \fmfshift{2 up}{oV}
    % main
    \fmf{fermion}{i1,v1,i2}
    \fmf{gluon,label=$g$,l.s=right,l.d=10}{v2,v1}
    \fmf{phantom,t=1.1}{o2,v2,o1}
    \fmffreeze
    \fmf{fermion}{o2,v2,vV,o1}
    \fmf{boson,t=0}{vV,oV}
    % labels
    \fmflabel{$q$}{i1}
    \fmflabel{$\overline{q}$}{i2}
    \fmflabel{$\overline{\mathrm{t}}$}{o2}
    \fmflabel{t}{o1}
    \fmfv{l.a=-15,l.d=4,l=Z}{oV}
  \end{fmfgraph*}
  } % close \fmfframe
\end{fmffile}
\end{document}