Searching for η-mesic Helium with WASA-at-COSY facility Oleksandr Rundel, Oleksandr Khreptak, Magdalena Skurzok, Wojciech Krzemien and Pawel Moskal EPJ Web Conf., 130 (2016) 02008 Published online: 29 November 2016 DOI: 10.1051/epjconf/201613002008