Study of ~9Be(γ, Pπ-) Reaction and its Comparison with QMD Calculation in the △ Resonance Region

摘要

We have studied the ~9Be(γ,pπ-) reaction at the incident photon energies from 260 to 420 MeV. The missing momentum and invariant mass distributions are well understood by a single quasi-free scattering picture. It is found that the separation energy of a neutron from the nucleus becomes gradually increasing as E_γ increases. The missing energy distribution is understood with two contributions from neutrons on the s- and p-shells. The relative strength of these contributions normalized to the neutron numbers on each shell increases almost linearly as E_γ increases, reflecting the fact that the normalized s-shell contribution increases monotonically with increasing E_γ The double differential cross section is compared with a simulation calculation of QMD model. The agreement between the calculation and the data is Well except for the data at the most forward proton angle and the Lowest E_γ.