% !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/VLQ_VLL$TAG.tex
\documentclass[11pt,border=4pt]{standalone}
\usepackage{feynmp-auto}
\usepackage{xcolor}
\definecolor{colVLL}{rgb}{0,0,1} % VLL (blue)
\usepackage{scalerel}
\newcommand{\mylbrace}[2]{\vspace{#2pt}\hspace{4pt}\scaleleftright[\dimexpr6pt+#1\dimexpr0.11pt]{\lbrace}{\rule[\dimexpr2pt-#1\dimexpr0.5pt]{-4pt}{#1pt}}{.}}
\newcommand{\myrbrace}[2]{\vspace{#2pt}\scaleleftright[\dimexpr6pt+#1\dimexpr0.11pt]{.}{\rule[\dimexpr2pt-#1\dimexpr0.5pt]{-4pt}{#1pt}}{\rbrace}\hspace{2pt}}
\definecolor{colBSM}{rgb}{.96,.3,0} % BSM mediator (orange)
\begin{document}
\begin{fmffile}{feyngraph}
  \fmfframe(3,13)(5,13){ % padding (L,T)(R,B)
  \begin{fmfgraph*}(90,65) % canvas (W,H)
    % line style
    \fmfset{wiggly_len}{12} % boson wavelength
    \fmfset{wiggly_slope}{65} % boson slope of waves
    % external vertices
    \fmfleft{d,i,d,d}
    \fmfright{o3,m,o2,o1}
    \fmftop{t} % for pulling
    \fmfshift{9 down}{o2}
    \fmfshift{4 left}{o3}
    % main process
    \fmf{fermion,f=(0,,0,,1),t=1.4}{i,v}
    \fmf{phantom}{v,m}
    \fmffreeze
    \fmf{boson,f=(.96,,.3,,0),t=1.5,label=\color{colBSM} U,l.s=left,l.d=4}{v,w}
    \fmf{fermion}{o2,w,o1}
    \fmf{fermion}{v,o3}
    \fmf{phantom,t=0.7}{w,t} % pull W decay vertex
    % labels
    \fmfv{l.d=5,l.a=180,l=\color{colVLL} E}{i}
    \fmfv{l.d=5,l.a=25,l=$\ell^\mp$}{o1}
    \fmfv{l.d=5,l.a=0,l=$\overline{\mathrm{q}}$}{o2}
    \fmfv{l.d=4,l.a=-25,l=b}{o3}
    %\fmfv{l.d=8,l.a=180,l=U}{w} % for boson line
  \end{fmfgraph*}
  } % close \fmfframe
\end{fmffile}
\end{document}