Proposal to search for a dark photon in e+ on target collisions at DAFNE linac

Photon-like particles are predicted in many extensions of the Standard Model. They have interactions similar to the photon, are vector bosons, and can be produced together with photons. The present paper proposes a search for such particles in the e^+e^- ->Ug process in a positron-on-target experiment, exploiting the positron beam of the DAΦNE LINAC at the Laboratori Nazionali di Frascati, INFN. With a 550 MeV/c beam and 104 positrons per bunch in one year of running a sensitivity in the relative coupling constant down to 10-6 is achievable, in the mass region from 2.5 MeV < MU < 20 MeV, compatible with the preferred region from the 3s discrepancy in g_m -2.The proposed experimental setup and the analysis technique is discussed.