\begin{table}%t3
\par
\caption{\label{tab: geometries}The ratio of the persistent over dipping radius 
$R_p/R_d$ for the two geometries and for each data group (A--C3).}
%\centering
\par
\begin{tabular}{cccccc}
\hline \hline
 & A & B & C1 & C2 & C3 \\
\hline 
case 1 & $1.7\pm0.4$ & $1.1\pm0.1$ & $1.7\pm0.2$ & $1.1\pm0.1$ & $1.3\pm0.1$ \\
case 2 & $30\pm13$ & $13\pm3$ & $30\pm6$& $11\pm2$ & $17\pm3$ \\
\hline
\end{tabular}
\end{table}