% !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$TAG.tex
\documentclass[11pt,border=4pt]{standalone}
\usepackage{feynmp-auto}
\usepackage{xcolor}
\definecolor{colvtx}{rgb}{0,.1,1} % LQ vertex (blue)
\begin{document}
\begin{fmffile}{feyngraph}
  \fmfframe(-10,11)(4,11){ % padding (L,T)(R,B)
  \begin{fmfgraph*}(120,70) % dimensions (WH)
    % line style
    \fmfset{dash_len}{10} % dashes length
    \fmfset{wiggly_len}{12} % boson wavelength
    \fmfset{wiggly_slope}{65} % boson slope of waves
    % external vertices
    \fmfleft{i2,i1}
    \fmfright{o2,o1}
    % qq -> LQ LQ
    \fmf{fermion}{i1,v1}
    \fmf{fermion}{v2,i2}
    \fmf{fermion,t=0.8,l.s=right,label=$\ell$}{v1,v2} % t-channel
    % outgoing LQs
    \fmf{dashes}{o1,v1}
    \fmf{dashes}{o2,v2}
    % vertices
    \fmfv{d.sh=circle,d.f=full,d.si=4,f=(0,,.1,,1),
          l=\color{colvtx}$\lambda$,l.d=7,l.a=90}{v1}
    \fmfv{d.sh=circle,d.f=full,d.si=4,f=(0,,.1,,1),
          l=\color{colvtx}$\lambda$,l.d=7,l.a=-90}{v2}
    % labels
    \fmfv{l.a=160,l.d=4,l=$q$}{i1}
    \fmfv{l.a=-160,l.d=4,l=$\overline{q}$}{i2}
    \fmfv{l.a=20,l.d=4,l=LQ}{o1}
    \fmfv{l.a=-20,l.d=5,l=$\overline{\mathrm{LQ}}$}{o2}
  \end{fmfgraph*}
  } % close \fmfframe
\end{fmffile}
\end{document}