  As shown in the \emph{EPR} paper (Einstein, Podolsky e Rosen, 1935), Quantum
Mechanics is a non-local Theory. The Bell theorem and the successive
experiments ruled out the possibility of explaining quantum correlations using
only local hidden variables models. Some authors suggested that quantum
correlations could be due to superluminal communications that propagate
isotropically with velocity \emph{$v_{t}>c$} in a preferred reference frame.
For finite values of \emph{$v_{t}$} and in some special cases, Quantum
Mechanics and superluminal models lead to different predictions. So far, no
deviations from the predictions of Quantum Mechanics have been detected and
only lower bounds for the superluminal velocities \emph{$v_{t}$} have been
established. Here we describe a new experiment that increases the maximum
detectable superluminal velocities and we give some preliminary results.
