% !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/ttbarqqbar$TAG.tex
\documentclass[11pt,border=4pt]{standalone}
\usepackage{feynmp-auto}
\begin{document}
\begin{fmffile}{feyngraph}
  \fmfframe(4,12)(7,10){ % padding (L,T)(R,B)
  \begin{fmfgraph*}(105,80) % dimensions (WH)
    % line style
    \fmfset{wiggly_len}{13} % boson wavelength
    \fmfset{wiggly_slope}{68} % boson slope of waves
    % external vertices
    \fmfstraight
    \fmfleft{i2,i1}
    \fmfright{o4,o3,o2,o1}
    \fmfshift{8 down}{i1}
    \fmfshift{8 up}{i2}
    % internal vertices (exact placement)
    %\fmfforce{(.30w,.80h)}{v1} % exact placement
    %\fmfforce{(.30w,.20h)}{v2} % exact placement
    \fmfforce{(.72w,.83h)}{vq1} % exact placement
    \fmfforce{(.72w,.17h)}{vq2} % exact placement
    % main
    \fmf{fermion,t=1.1}{i1,v1}
    \fmf{fermion,t=1.1}{v2,i2}
    \fmf{fermion,t=0.7}{v1,v2} % t-channel
    \fmf{gluon}{vq1,v1}
    \fmf{gluon}{v2,vq2}
    % g -> tt
    \fmf{fermion}{o2,vq1,o1}
    \fmf{fermion}{o4,vq2,o3}
    % labels
    \fmfv{l.a=150,l.d=5,l=$q$}{i1}
    \fmfv{l.a=-150,l.d=5,l=$\overline{q}'$}{i2}
    \fmfv{l.a=30,l.d=5,l=t}{o1}
    \fmfv{l.a=-20,l.d=5,l=$\overline{\mathrm{t}}$}{o2}
    \fmfv{l.a=30,l.d=5,l=t}{o3}
    \fmfv{l.a=-20,l.d=5,l=$\overline{\mathrm{t}}$}{o4}
  \end{fmfgraph*}
  } % close \fmfframe
\end{fmffile}
\end{document}