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\begin{document}
  
  \begin{tabular}{lr@{$\pm$}l} 
   {Variable}  &  \multicolumn{2}{c}{Fit results} \\
   \hline
   $M_{ B\xspace\xspace^0\xspace}$                 &\phantom{0}5280.83 & 0.04  $ {\mathrm{\,Me\kern -0.1em V\!/}c^2}$ \xspace\\
   $\sigma_{ B\xspace\xspace^0\xspace}$            &\phantom{0}5.77    & 0.05  $ {\mathrm{\,Me\kern -0.1em V\!/}c^2}$ \xspace\\
   Signal yield              &\phantom{0}23,801  & 158\\
   Background yield          &\phantom{0}757     & 14\\       
    \end{tabular}
    
    
    
  
\end{document}
