
\documentclass[border=5pt,multi=true]{standalone}
\usepackage{standalone}
\usepackage{lineno}
\usepackage{graphicx}
\usepackage{xspace}
\usepackage{color}
\usepackage{colortbl}
\usepackage{amsmath}
\usepackage{ifthen}
\usepackage{ulem}
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\usepackage{upgreek}
\usepackage{hyperref}
\usepackage{hypcap}
\usepackage{rotating}
\usepackage{multirow}
\usepackage{graphpap}
\usepackage{subfigure}
\usepackage{wasysym}
\usepackage{array}
\usepackage{pifont}
\usepackage{cite}
\usepackage{mciteplus}


\graphicspath{{./figs/}}

\begin{document}
\DeclareGraphicsExtensions{.pdf}
\setlength{\unitlength}{1mm}
  \centering
  \begin{picture}(150,120)
    \put(0,60){
      \includegraphics*[width=75mm,height=60mm,%
      ]{Fig2a.pdf}
    }
    \put(77,60){
      \includegraphics*[width=75mm,height=60mm,%
      ]{Fig2b.pdf}
    }
    \put(0,0){
      \includegraphics*[width=75mm,height=60mm,%
      ]{Fig2c.pdf}
    }
    \put(77,0){
      \includegraphics*[width=75mm,height=60mm,%
      ]{Fig2d.pdf}
    }
    \put(42,111) { \small  $\ensuremath{\ensuremath{\ensuremath{D}\xspace}\xspace^0}\xspace \ensuremath{\rightarrow}\xspace \mathrm{K}^- \ensuremath{\ensuremath{\ensuremath{\pi}\xspace}\xspace^+}\xspace$       } 
    \put(90,112) { \small  $\ensuremath{\ensuremath{\ensuremath{D}\xspace}\xspace^+}\xspace \ensuremath{\rightarrow}\xspace \mathrm{K}^- \ensuremath{\ensuremath{\ensuremath{\pi}\xspace}\xspace^+}\xspace{}\ensuremath{\ensuremath{\ensuremath{\pi}\xspace}\xspace^+}\xspace$ }
    \put(42,52)  { \small  $\ensuremath{\ensuremath{\ensuremath{D}\xspace}\xspace^+_\ensuremath{\ensuremath{s}\xspace}\xspace}\xspace \ensuremath{\rightarrow}\xspace \mathrm{K}^+ \mathrm{K}^- \ensuremath{\ensuremath{\ensuremath{\pi}\xspace}\xspace^+}\xspace$}
    \put(90,52)  { \small  $\ensuremath{\ensuremath{\Lambda}\xspace_\ensuremath{\ensuremath{c}\xspace}\xspace^+}\xspace \ensuremath{\rightarrow}\xspace \mathrm{p} \mathrm{K}^- \ensuremath{\ensuremath{\ensuremath{\pi}\xspace}\xspace^+}\xspace$ } 
    \put(30,1)   { $m_{\left(\mathrm{K^+K^-}\right)_{\ensuremath{\phi}\xspace}\ensuremath{\ensuremath{\ensuremath{\pi}\xspace}\xspace^+}\xspace}$}
    \put(105,1)  { $m_{\mathrm{p}\mathrm{K}^{-}\ensuremath{\ensuremath{\ensuremath{\pi}\xspace}\xspace^+}\xspace}$}
    \put(30,61)  { $m_{\mathrm{K}^{-}\ensuremath{\ensuremath{\ensuremath{\pi}\xspace}\xspace^+}\xspace}$}
    \put(105,61) { $m_{\mathrm{K}^{-}\ensuremath{\ensuremath{\ensuremath{\pi}\xspace}\xspace^+}\xspace\ensuremath{\ensuremath{\ensuremath{\pi}\xspace}\xspace^+}\xspace}$}
    \put(55,1)   { $\left[ \mathrm{GeV}/c^2\right]$}
    \put(132,1)  { $\left[ \mathrm{GeV}/c^2\right]$}
    \put(55,61)  { $\left[ \mathrm{GeV}/c^2\right]$}
    \put(132,61) { $\left[ \mathrm{GeV}/c^2\right]$}
   \put(-3, 27){ \small %
     \begin{sideways}%
       $\tfrac{\mathrm{dN}}{\mathrm{d}m_{\mathrm{KK}\ensuremath{\pi}\xspace}}~~\left[\tfrac{1}{1~\mathrm{MeV}/c^2}\right]$
     \end{sideways}%
   }
   \put(-4, 89){ \small%
     \begin{sideways}%
       $\tfrac{\mathrm{dN}}{\mathrm{d}m_{\mathrm{K}\ensuremath{\pi}\xspace}}~~\left[\tfrac{1}{1~\mathrm{MeV}/c^2}\right]$
     \end{sideways}%
   }
   \put(73, 28){ \small %
     \begin{sideways}%
       $\tfrac{\mathrm{dN}}{\mathrm{d}m_{\mathrm{pK}\ensuremath{\pi}\xspace}}~~\left[\tfrac{1}{1~\mathrm{MeV}/c^2}\right]$
     \end{sideways}%
   }
   \put(73 , 87){ \small %
     \begin{sideways}%
       $\tfrac{\mathrm{dN}}{\mathrm{d}m_{\mathrm{K}\ensuremath{\pi}\xspace\ensuremath{\pi}\xspace}}~~\left[\tfrac{1}{1~\mathrm{MeV}/c^2}\right]$
     \end{sideways}%
   }
    \put(130,47){ \small %
      $\begin{array}{r}
        \mathrm{LHCb}~%
      \end{array}$
    }
    \put(130,107){ \small %
      $\begin{array}{r}
        \mathrm{LHCb}~ %
      \end{array}$
    }
    \put( 11,47){ \small %
      $\begin{array}{l}
        \mathrm{LHCb}~%
      \end{array}$
    }
    \put( 11,107){ \small %
      $\begin{array}{l}
        \mathrm{LHCb}~%
      \end{array}$
    }
   \put( 12,112)   { a) }
   \put(140,112)   { b) }
   \put( 12, 52)   { c) }
   \put(140, 52)   { d) }
  \end{picture}
\end{document}
