A search for new light charged particles in photoproduction V.I. Alekseev, V.A. Baskov, V.A. Dronov, Yu.F. Krechetov, A.I. L’vov, L.N. Pavlyuchenko, V.V. Polyanskiy and S.S. Sidorin EPJ Web Conf., 204 (2019) 08009 Published online: 03 April 2019 DOI: 10.1051/epjconf/201920408009