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\begin{document}
    \footnotesize
         
    
\begin{subtable}[t]{\textwidth}
    \begin{tabular}{lc} 
        \multicolumn{2}{c}{a) \footnotesize $ 0 \leq {p_{\mathrm{L}}^{ B\xspace\xspace}}\xspace < 75 \text{\,Ge\kern -0.1em V\!/}c\xspace$} \\
        \\ 
        \toprule
        Range [ $\text{\,Ge\kern -0.1em V\!/}c$ \xspace] &  $\mathcal{R}$\\
        \midrule 
        $0.5 <  { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace < 4 $   & $0.124 \pm 0.002$ \\
        $4 <    { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace <6$     & $0.127 \pm 0.003$ \\
        $6 <    { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace <8$     & $0.129 \pm 0.003$ \\
        $8 <    { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace <11$    & $0.125 \pm 0.004$ \\
        $11 <    { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace <40$   & $0.119 \pm 0.006$ \\ 
        \bottomrule
    \end{tabular}    
    \begin{tabular}{lc} 
        \multicolumn{2}{c}{b) \footnotesize $ 75 \leq {p_{\mathrm{L}}^{ B\xspace\xspace}}\xspace < 125 \text{\,Ge\kern -0.1em V\!/}c\xspace$} \\
        \\ 
        \toprule
        Range [ $\text{\,Ge\kern -0.1em V\!/}c$ \xspace] &  $\mathcal{R}$\\
        \midrule 
        $0.5 <  { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace < 4 $  & $0.128 \pm 0.003$ \\
        $4 <    { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace <6$     & $0.132 \pm 0.003$ \\
        $6 <    { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace <8$     & $0.128 \pm 0.003$ \\
        $8 <    { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace <11$    & $0.129 \pm 0.003$ \\
        $11 <    { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace <40$   & $0.119 \pm 0.003$ \\
        \bottomrule
    \end{tabular}    
    \begin{tabular}{lc} 
        \multicolumn{2}{c}{c) \footnotesize $ 125 \leq {p_{\mathrm{L}}^{ B\xspace\xspace}}\xspace < 700 \text{\,Ge\kern -0.1em V\!/}c\xspace$} \\
        \\ 
        \toprule
        Range [ $\text{\,Ge\kern -0.1em V\!/}c$ \xspace] &  $\mathcal{R}$\\
        \midrule 
        $0.5 <  { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace < 4 $  & $0.131 \pm 0.004$ \\
        $4 <    { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace <6$     & $0.128 \pm 0.004$ \\
        $6 <    { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace <8$     & $0.127 \pm 0.003$ \\
        $8 <    { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace <11$    & $0.123 \pm 0.003$ \\
        $11 <    { p_{\mathrm{T}}\xspace^{ B\xspace\xspace}}\xspace <40$   & $0.121 \pm 0.002$ \\
        \bottomrule
    \end{tabular}    
    \end{subtable}
\end{document}
