Information on the nucleon-isobar content in helium from 5 GeV pion-helium interactions

Missing mass spectra from the reactions πp --> πx and πα --> πtx have been measured and found to be significantly different. Neglecting all background processes an analysis with the impulse approximation yields a 0.24 percent presence of the isobar-triton state in helium in the triton momentum range 0.32-0.70 GeV/c and the mass range 1.30-1.86 GeV/c².