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

Abstract Missing mass spectra from the reactions π p → π x and πα → π tx 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 c 2 .