Neutral and Charged Decay Modes of the X17 Boson Observed in dCu Collisions at a Momentum of 3.8 GeV/c per Nucleon

Earlier (see [1]) we reported the observation of structures at about 17 and 38 MeV/c2 in the invariant mass spectra of photon pairs. The results of testing of the observed signals, including the results of the Monte Carlo simulation support the conclusion that the observed signals are the consequence of detection of the particles with masses of about 17 and 38 MeV/c2 decaying into a pair of photons. A comparative analysis of two series of measurements with two scintillation counters switched on in coincidence and without them, all other conditions being equal, are performed. Thus, together with the decay mode of X17 into two photons, the charged mode ( $${{e}^{ + }}{{e}^{ - }}$$ ) of the decay of X17 is also confirmed. According to preliminary estimates, the partial widths of these decays are comparable.