% !TEX program = pdflatexmk
% !TEX parameter = -shell-escape
% Author: Izaak Neutelings (March 25)
% Instructions: To compile via command line, run the following twice
%   pdflatex -shell-escape extract/LQ$TAG.tex
\documentclass[11pt,border=4pt]{standalone}
\usepackage{feynmp-auto}
\usepackage{xcolor}
\definecolor{colqcd}{rgb}{1,0,0} % strong vertex (red)
\begin{document}
\begin{fmffile}{feyngraph}
  \fmfframe(-8,16)(6,17){ % padding (L,T)(R,B)
  \begin{fmfgraph*}(120,70) % dimensions (WH)
    % line style
    \fmfset{dash_len}{10} % dashes length
    \fmfset{wiggly_len}{12} % boson wavelength
    \fmfset{wiggly_slope}{65} % boson slope of waves
    % external vertices
    \fmfleft{i2,i1}
    \fmfright{o2,o1}
    % gg -> g
    \fmf{gluon}{i2,v1,i1}
    \fmf{gluon,t=1.1}{v1,v2} % s-channel
    % g -> LQ LQ
    \fmf{dashes,t=1.2}{o1,v2}
    \fmf{dashes,t=1.2}{o2,v2}
    % vertex
    \fmfv{d.sh=circle,d.f=full,d.si=4,f=(1,,0,,0),
          l=\strut\color{colqcd}$\alpha_\mathrm{s}$,l.d=6,l.a=0}{v2}
    % labels
    \fmfv{l.a=150,l.d=4,l=$g$}{i1}
    \fmfv{l.a=-150,l.d=4,l=$g$}{i2}
    \fmfv{l.a=25,l.d=3,l=LQ}{o1}
    \fmfv{l.a=-25,l.d=4,l=$\overline{\mathrm{LQ}}$}{o2}
  \end{fmfgraph*}
  } % close \fmfframe
\end{fmffile}
\end{document}