Search for neutron dark decay: n → χ + e+e− X. Sun, E. Adamek, B. Allgeier, M. Blatnik, T.J. Bowles, L.J. Broussard, M.A.-P. Brown, R. Carr, S. Clayton, C. Cude-Woods et al. (50 more) EPJ Web Conf., 219 (2019) 05008 Published online: 13 December 2019 DOI: 10.1051/epjconf/201921905008