Dark decay channel analysis (n → χ + e+ e−) with the PERKEO II experiment Michael Klopf, Erwin Jericha, Bastian Märkisch, Heiko Saul, Torsten Soldner and Hartmut Abele EPJ Web Conf., 219 (2019) 05007 Published online: 12 December 2019 DOI: 10.1051/epjconf/201921905007