KLOE/KLOE-2 results and perspectives on dark force search

Different astrophysical anomalies could find explanation on the existence of a new kind of matter, dark matter, stimulating the search for mediator of a new force, called dark photon (U boson, $A^\prime$), coupling weakly with Standard Model particles. The KLOE experiment searched for the existence of the dark photon investigating three different processes: dalitz decays of the $\Phi$ meson $\Phi\to \eta U$, the production from continuum $e^+e^- \to U \gamma$, the dark Higgsstrahlung $e^+e^- \to Uh'$. No evidence was found and limits on the model parameters have been set at 90\% confidence level. A reanalysis on the $e^+e^- \to U \gamma$ with U decaying into muon pairs at 1.93 fb$^{-1}$ was performed and new preliminary 90\% CL upper limits obtained with this data sample and by the combination of these events with the U boson decaying into pions pairs will be presented. The upgraded detector KLOE-2 is collecting data with new beam crossing scheme of \DAF\ since November 2014. The analyses of new data could improve the sensitivity of these investigated processes by a factor two profiting of the higher statistics and the improvement on the momentum and interaction vertex resolution. Moreover, a single photon trigger has been implemented in data taking and will allow the search of the dark photon through its invisible decays in light dark matter particles.