Possible contribution of a highly excited collective state to proton-nucleus multistep interactions at 300 MeV

Intermediate-energy nucleon-nucleus interactions were investigated in order to achieve a more comprehensive understanding of spallation reactions. Inclusive ¹²C(p,p′) spectra at 300 MeV were measured in a wide energy range and compared with two theoretical calculations: the quantum molecular dynamics model and the intranuclear cascade model. The calculations are in good agreement with the experimental results in the quasifree region. In the lower energy domain, however, the calculations underestimated the experimental results by a factor of about 2. The cause of the discrepancy was discussed in terms of a collective excitation process.