Search for light dark photon with neutral meson decays at the PHENIX experiment

In several theoretical models, an additional U(1) gauge field for dark matter has been introduced to explain experimental results deviating from the standard model calculations. The gauge boson of the U(1) gauge field, a so-called "dark photon", can mix with QED photons in any photon production process owing to very weak coupling of the U(1) gauge field to the standard model. The dark photon has been relevant recently to explain 3.6 sigma discrepancy of the measured muon anomalous magnetic moment (g 2) from the standard model calculations. The PHENIX experiment has made a search for electron pairs from dark photons appearing within 0,77 Dalitz decays. Upper limits on the dark photon mixing strength has been determined for 30 < m(v) < 90 MeV/c(2). Combining with relevant results from other experiments, the possibility of the explanation of the measured (g - 2)(mu) by the dark photon is ruled out.