PHELEX with a Multi-Cathode Counter in the Search for Dark Photons

In this paper, we report the results obtained in the PHoton–ELectron EXperiment (PHELEX) during two series of measurements, each consisting of 4 Runs about 50 days each Run. We have observed a systematic excess of single-electron events in each series of measurements. In the first one we have observed it with a confidence level better than 6 \(\sigma\) , in the time interval from \(8:00\) to \(12:00\) in sidereal time. In the second one with a confidence level better than 4 \(\sigma\) , in the time interval from \(18:00\) to \(22:00\) in sidereal time. No similar effect was observed in the solar time. The fact that we observe this effect in the stellar frame but no similar effect in the solar frame suggests that probably this effect is of galactic origin. To check this hypothesis, we are conducting further measurements.