Abstract: The complete large and clean sample of e+e- collisions recorded by the BaBar detector at PEP-II at the SLAC National Laboratory was used to search for a photon-like particle with mass and decaying into an e+e- or μ+μ- pair, which is proposed in some Dark Matter theory models, and to search for a long-lived particle that decays into an oppositely charged fermion pair, predicted in a number of New Physics models. We do not observe a significant signal and we set 90% confidence level upper limits of several production rates and on the parameters of some proposed New Physics models.

Key words: New Physics, Dark Matter, B-factory