G. Backenstoss et al., CONTRIBUTION OF INITIAL-STATE INTERACTIONS TO THE 3-NUCLEON ABSORPTION OF PIONS BY HE-3, Physics letters. Section B, 379(1-4), 1996, pp. 60-66
The distributions of protons after the absorption of positive pions by
He-3 at 118, 162 and 239 MeV are presented. A decomposition of the th
ree-nucleon cross section in terms of initial state interactions acid
other processes is given, based upon simple models. A clear signal of
initial state interactions is visible in the data, diminishing at the
lower energies.