% !TEX program = pdflatexmk
% !TEX parameter = -shell-escape
% Author: Izaak Neutelings (September 24)
% Instructions: To compile via command line, run the following twice
%   pdflatex -shell-escape extract/ttbar$TAG.tex
\documentclass[11pt,border=4pt]{standalone}
\usepackage{feynmp-auto}
\begin{document}
\begin{fmffile}{feyngraph}
  \fmfframe(-6,18)(-5,16){ % padding (L,T)(R,B)
  \begin{fmfgraph*}(120,75) % dimensions (WH)
    % line style
    \fmfset{wiggly_len}{12} % boson wavelength
    \fmfset{wiggly_slope}{65} % boson slope of waves
    \fmfleft{i2,i1}
    \fmfright{o2,o1}
    \fmftop{t}
    \fmfshift{4 left}{i1}
    \fmfshift{2 left}{i2}
    \fmfshift{5 up}{t}
    % skeleton
    \fmf{phantom}{i1,v1,i2}
    \fmf{phantom}{o1,v2,o2}
    \fmf{phantom,tension=1.2}{v1,v2}
    \fmffreeze
    % main
    \fmf{gluon,tension=0.8}{g,i1}
    \fmf{fermion}{v1,g}
    \fmf{fermion}{i2,v1}
    \fmf{fermion,tension=0}{g,t}
    \fmf{gluon}{v1,v2}
    \fmf{fermion}{o2,v2,o1}
    % labels
    %\fmflabel{$g$}{i1}
    %\fmflabel{$g$}{i2}
    \fmfv{l.d=4,l=$g$}{i1}
    \fmfv{l.d=6,l=$q$}{i2}
    \fmfv{l.d=5,l.a=25,l=$q$}{t}
    \fmflabel{$\bar{\mathrm{t}}$}{o2}
    \fmflabel{$\mathrm{t}$}{o1}
  \end{fmfgraph*}
  } % close \fmfframe
\end{fmffile}
\end{document}