Two-deuteron photodisintegration of 4He at Eγ=150-250 MeV
We have performed a measurement of the cross section for the 4He(γ,dd) reaction with photon energies between 150 and 250 MeV. Both reaction particles were detected in coincidence. We obtained absolute cross sections at six angles and two energy bins (150-190 MeV and 190-250 MeV). A Legendre polynomial fit to the angular distribution shows a sin2 θ distribution which suggests the isospin-forbidden E1 transition. However, a transition matrix element (TME) analysis using only strictly allowed transitions shows that the angular distribution can be described by just two TMEs: E2 s- and d-wave absorption on the D state of 4He. We performed an inverse direct-capture calculation in order to determine if the D state could contribute to such a high degree to the cross section. This calculation indicates that 90% of the cross section arises from absorption on the D state but fails to reproduce the observed sin2 θ angular distribution.
Duke Scholars
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- Nuclear & Particles Physics
- 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
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Published In
EISSN
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Nuclear & Particles Physics
- 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics