This is the first measurement of the total cross section σ(4He (γ npp)n) in the range of 135-455 MeV. The σ, which cannot be reproduced by any model, has similar Eγ dependence to γT(γ4He → all channels). The averaged ratio σ(4He(γ, npp)n)/ σT(γ4 He → all channels) = (2.3 ± 0.3)% is compared with a cascade-model calculation in which quasi-free pion production followed by pion reabsorption is assumed.
ASJC Scopus subject areas
- Nuclear and High Energy Physics