Searching for 9 He upon the Absorption of Stopped Pions by 14 C Nuclei

An experimental search is conducted for the formation of the heavy 9He isotope of helium upon the absorption of stopped pions by 14C nuclei. The structure of 9He levels in the missing mass spectra in reactions 14C(π–, p4He)Х and 14C(π–, d3He)Х is studied. A state with a high energy of excitation of 12.5 MeV and a state width of 1.5 MeV is detected for the first time. Suppression of the formation of ground state 9He in the considered reactions is established.